With Zynga about to IPO with a value of around $10 billion, it's clear that games are more than just popular on Facebook, they're also highly lucrative.

Kickstarting the second Evolve London on-day conference, Gareth Davis, Facebook's games platform manager, expanded the case, arguing that the social platform was something all game developers should be using.

"You shouldn't think that Facebook is a website. It's a multi-device platform that provides social services for all game developers," Davis explained.

Of course, with 800 million monthly active users and 500 million daily active users - 200 million of whom play games on Facebook - there's a huge audience to address.

We're everywhere

"We're seeing Facebook integration across all platforms - from great integration in EA's Pogo.com, to people hooking up with their old college friends to play StarCraft II on PC or Uncharted 3 on console," Davis said.

"We're very excited about mobile too, from games such as FarmVille, Bejeweled and Words with Friends, these are highly integrated experiences."

Mobile is a platform that Facebook is pushing hard, partly as it has around 350 million users on mobile - providing interesting promotional opportunities - while it's also looking to the potential of location services.

"Location is just getting started but it's very powerful," Davis said.

Fragmenting multi-platform

Of course, this single game per platform approach is evolving quickly with titles being made available across platforms, with Facebook social features enriching play as you move from gaming via a mobile session while on the move to PC or console play in the evening. Facebook providing the social glue.

However, Davis argued that a next step Facebook's social graph will enable developers to open up much broader experiences whereby an overall game becomes synchronous, co-operative and team-based - and spread between platforms, with different companion gameplay on each.

"I think we'll see games with different components that are specific to the device you're playing on so you could have people on PC with a mouse and keyboard playing a more strategy element, whereas mobile players could use location-based elements," he predicted.

Tagged for the future

However, when it comes to Facebook's current platform focus, it's mobile, mobile, mobile.

"Our goal is to make Facebook available multi-platform, but especially on mobile, it's the hot sector at the moment," Davis said.

"Facebook has 350 million mobile users and it's increasing fast as everyone switches to smartphones. "

Of course, there are obvious benefits for integrating the Facebook SDK in native apps, such as access to all the data of Facebook users and access to channels such as News Feeds.

And there's much more than can be done.

"We're doing a lot of work on mobile web, especially on HTML5. You can do great games in the browser, but you have to build your game to deal with the current performance issues," he said.

"This is getting solved as WebGL arrives, but don't try and build a 3D shooter in HTML5 yet."

"HTML5 is going to be the future of web. It's just how long it will take until we can make all type of games using it."