[Every other week, we examine the most popular Facebook games (according to monthly active users), looking at the top titles and developers on the social network to see who's attracting or losing players.]

In our last tally of the most popular Facebook games -- before a bug appeared in the social network's user reporting data, providing inaccurate headcounts for some applications -- Zynga dominated the top ten list with its titles taking seven spots.

Not much has changed in that respect with this latest chart, as super popular farming simulator FarmVille remains at the top with around 62 million users, only a few hundred thousand players more than its count over a month ago.

FrontierVille has enjoyed much growth, though, as it's now #2 with 36.8 million users, nearly doubling in size since late July. Texas Holdem Poker at #3 has also seen its audience swell in recent weeks, as its now has 32.9 million card players, likely boosted by the launch of a localized Traditional Chinese version last month.

The recent launch of its Las Vegas expansion has helped push Zynga's Mafia Wars to #4 with 25.1 million users playing. The mob game is followed by Zynga's Cafe World (22.5 million), Treasure Isle (16 million), and PetVille (14.3 million).

At #8, Mindjolt Games, a portal for more than a thousand casual titles, is the first non-Zynga app to appear on the chart with its 14 million players. Electronic Arts/Playfish's Pet Society at #9 (13.5 million) and PopCap's Bejeweled Blitz at #10 (12.5 million) fill out the rest of the top ten chart.

You can see the full list of the top 20 Facebook games along with exact monthly active user counts below:

Finnish social game developer Rocket Pack (Cats Vs. Dogs) has created a new development platform specifically designed for creating persistent browser games that don't require plugins.

The company describes its Rocket Engine as a "fully integrated toolkit for plugin-free browser game development." The company will bundle a components library and editing tools with the kit, which it also says includes live previews and support for multiple users, and will launch in Q4 2010.

Rocket Engine supports development for major browsers and social gaming platforms, including the iPhone, iPad and Android devices. It's described as a component-based toolkit, aimed to enable game developers to prototype quickly and develop their online games. It includes an online editor, which the company hopes will ease on-the-go editing, as it doesn't require coding.

"Our [studio] was used to professional tools such as the Unreal Engine or Unity3D," said Jiri Kupiainen, one of the founders of Rocket Pack. "But nothing existed for professional plugin-free browser game development, so we built it ourselves."

The company is developing its own social MMO called Cats vs. Dogs, which will be released later this year, and recently secured funding from the Nordic Game organization.

The development platform is integrated with the company's Rocket Network, which provides cloud services for MMO development including identity handling, virtual currencies and full tracking and reporting for custom metrics.

GDC Online organizers are reminding potential attendees that today is the last day to save up to 40% on passes to the October 5th-8th event in Austin, TX, fully detailing the comprehensive exhibit floor, Summits, keynotes, a PlayStation Home developer day and more.

The Austin, Texas based GDC Online conference -- formerly known as GDC Austin -- is mainly focused on the development of online games, including free-to-play titles, social network games, and traditional MMOs, with a veteran online game industry advisory board evaluating and selecting the lectures.

There are now more than 120 panels, lectures and tutorials currently scheduled for the event -- including the recently announced keynote from Civilization II designer and now Zynga chief game designer Brian Reynolds (FrontierVille), and just-debuted track keynotes from Blizzard on Battle.net, Raph Koster on social design trends, and European browser game giant BigPoint on its rise to success.

These lectures join a full set of highlighted lectures including Main Conference talks on October 6th-8th from Relic, Sony Online, Carbine, KingsIsle, IMVU, Disney, Playdom, BioWare Austin, Hangout Industries, Broken Bulb Studios, CCP, Gaia Online, Playfish, InstantAction, Ubisoft and a host of other notable companies at the leading worldwide online game-specific conference.

One of the other major advantages of attending GDC Online is the comprehensive list of nearly 90 exhibitors with whom attendees are able to get product demonstrations, meet, and interact on the vibrant GDC Online Expo Floor. These include major firms like Epic, Rackspace, Gaikai, Offerpal, Vindicia, Trinigy, ARIN, Versant, Rixty, Softlayer, and many other notable companies in the space.

Retailer Target announced that it will be the first brick-and-mortar chain to sell gift cards for Facebook Credits, the social network's universal virtual currency system.

The gift cards, which are available in increments of $15, $25, and $50 (the $15 card will be exclusively available at Target) will begin rolling out to the retailer's more than 1,700 locations across the country on September 5th.

With the cards, Facebook users will be able to buy virtual currency and goods in over 150 social games and apps that support Credits, without needing to use a credit card or provide personal details. Many popular titles offer Credits as a payment option, including FarmVille, Mafia Wars, and Bejeweled Blitz.

Prepaid cards for Facebook games are typically limited to a particular title or publisher -- Target also sells cards for individual titles and companies, like YoVille and Playdom -- but Credits are designed to provide a more portable alternative to those game/app- or publisher-specific virtual currencies.

Though the Credits system is still in beta, many major developers have already pledged to use the social network's universal virtual currency exclusively in their titles. Playdom, RockYou, and CrowdStar have gone so far as to sign five-year agreements with Facebook to only use Credits.

"At Target we strive to delight our guests with exciting, new products every day, so we're thrilled to be the first retailer to sell Facebook Credits gift cards," says Target's Merchandising SVP Mark Schindele.

Schindele adds, "With social gaming becoming increasingly popular, Facebook Credits gift cards provide an easy and convenient option for Target guests to purchase virtual goods."

In April of this year, mobile social network operator and game creator DeNA announced a partnership with Yahoo! Japan to launch a PC web-based gaming platform called Yahoo! Mobage. While developers have been allowed access since January, the Yahoo! Mobage service is now aiming for its public launch of the 1st of October.

Yahoo! Mobage provides services such as translation, hosting and monetization resources. DeNA is currently inviting American PC and mobile game developers to use a universal Mobage platform API to distribute their games to the Japanese market.

The platform offers the advantage of two user bases of significant size: Yahoo's 52 million monthly active web-based users and DeNA's 20 million active mobile users. Including other sources, it's believed that the Mobage platform will reach an average of 90 million Japanese internet users.

DeNA will also offer several forms of aid for interested developers, including partnerships with four companies to assist in game testing and translation, money transfers through international banks, and hosting through the leading Japanese service provider, IDC Frontier.

DeNA's CEO, Tomoko Namba, claims that the amount of money to be made in Japanese social gaming as "astronomical... by offering this platform and providing tools to help ease the transition, DeNA hopes to be American game developers' portal to the East," Namba says. Some Japanese developers on Mobage are already making an average of $1 million a month in their top games.

DeNA has seen significant gains in the social gaming market this year, with an 81 percent year-over-year increase to $205 million reported in its fourth quarter, partly due to the success of its self-created social game titles.

The Tokyo-based company launched in 1999 as an e-commerce business and later became a web service provider for PC and cell phone users. Its core social networking/virtual world platform Mobage-town currently has over 20 million members in Japan.

Publisher Electronic Arts has announced that its major retail title Madden NFL 11, which launched earlier this month for PlayStation 2 & 3, Xbox 360, Wii, and PSP, is currently the number one selling game for August in the North American market, according to its internal tracking.

Sales are projected to be up approximately 5 percent year-over-year across all platforms for the month, according to a statement released by the company this afternoon.

In analyst note following the statement, Lazard Capital Markets' Colin Sebastian commented on the gains, suggesting that the franchise appears to be benefiting from improved gameplay, citing EA's press release -- which notes that 85 percent of users have used the new streamlined "GameFlow" play calling feature.

EA says that GameFlow "streamlines play calling and shortens overall game length for a more accessible experience. "

Simultaneously, EA Sports president Peter Moore announced via his EA Sports blog that card-and-management game Madden NFL Superstars has launched on Facebook.

The game, which is accessible here, borrows the concept of card-based teams from the Madden Ultimate Team DLC pack for Madden NFL 10.

It was created by the team at EA-owned social gaming company Playfish, who is also behind the Facebook-based EA Sports licensed title FIFA Superstars.

Game engine developer Trinigy has integrated Allegorithmic's Substance Air and Redux products into its Vision Engine 8, additions designed to offer online developers faster access to lightweight textures.

According to the company, Substance Air enables developers to create small but high-quality textures for MMO and browser-based titles, while Substance Redux is a compression tool intended to reduce the size of bitmap textures while minimizing quality and performance losses in-game.

Trinigy says that by integrating the runtimes of both products in Vision Engine 8, online and browser-based game developers can load Allegorithmic's texture formats directly within the Vision Engine tools pipeline (e.g. Vision Engine's scene editor VForge).

"Trinigy has always worked closely with its customers and partners to provide a solution that not only boosts game performance across platforms, but that increases workflow productivity in the game development process," says Trinigy's managing director Dag Frommhold.

He adds, "This new integration with Allegorithmic’s products achieves all of those goals. Not only was this integration highly requested by our growing MMO and browser game customer base; it speeds a developer’s access to textures that are perfectly suited for streaming game environments and tiny download needs."

London-based casual/social gaming start-up Zattikka announced its appointment of Jim McDonagh, who has worked at a variety of developers like NCSoft and Sega Europe, as external producer.

McDonagh most recently served as an external producer at Sega Europe, where he worked with The Creative Assembly to release BAFTA award-winning strategy title Empire: Total War. Before that, he helped NCSoft develop several of the company's MMO games. He's also spent three years apiece at Ubisoft and Eidos Interactive.

While at Zattikka, McDonagh is tasked with overseeing and shaping the studio's new talent and intellectual properties. The firm raised $5.5 million through its parent company Expedite last month, which it is investing in recruitment, research and development, and marketing to further expand its catalog of browser and mobile titles.

Since its opening last year, Zattikka has grown its library to more than 100 titles, putting out at least two new games each week. The company's releases attract a total of more than one monthly unique users.

The announcement of McDonagh's hiring follows a week after Zattikka revealed its hiring of Peter Jones, a Codemasters and Lionhead veteran who has worked in the games industry for 20 years, as its executive producer.

"I’m delighted we’ve hired Jim, with his wealth of games industry experience, demonstrating our ability to attract high quality people into our expanding team," says Zattikka Founder and CEO Tim Chaney. "He will be pivotal in acquiring and managing the development of high quality games for our rapidly developing portal business."

A day before the GDC Online early deadline, the major October 5th-8th Austin-based event has added track keynotes from Blizzard's Greg Canessa (on Battle.net), Playdom's Raph Koster (on social mechanics), and Bigpoint's Heiko Hubertz (on the rise of Europe in online gaming).

The Austin, Texas based GDC Online conference -- formerly known as GDC Austin -- is sharply focused on the development of online games, including free-to-play titles, social network games, and traditional MMOs, with a veteran online game industry advisory board evaluating and selecting the lectures.

There are now more than 120 panels, lectures and tutorials currently scheduled for the October 5th-8th event -- and following the announcement of a keynote from Civilization II designer and now Zynga chief game designer Brian Reynolds (FrontierVille), three track keynotes are debuting.

The brand-new track keynotes across the GDC Online Main Conference, which takes place from Wednesday October 6th to Friday October 8th, and for which majorly discounted passes are only available until Wednesday, are:

- In a production track keynote called 'Battle.net: A Postmortem', Blizzard's Battle.net project director Greg Canessa and technical director Matt Versluys will present an extremely rare lecture from the World Of Warcraft and Starcraft II creators, "sharing lessons learned from building and launching the new iteration of an online game service that connects and powers all Blizzard titles."

- Playdom's VP of creative design Raph Koster -- a stalwart of online game design from Ultima Online through Star Wars Galaxies to his current work in social games -- presents a design track keynote, 'Classic Social Mechanics: The Engines Behind Everything Multiplayer'.