Facebook passes 250 million mobile users mark, overhauls mobile site

Facebook has started to roll out a major upgrade to the mobile version of its site (m.facebook.com) that "delivers the best possible mobile Web experience no matter what device you're using." Previously, Facebook had two mobile versions: m.facebook.com for lower-end basic mobile devices and touch.facebook.com for high-end touchscreen devices.

Facebook says it found two major problems with this approach:

1. We were limited by the lowest common denominator for each site. We couldn't use JavaScript and had device specific file size limitations on m.facebook.com. Supporting a wide array of touch phones of varying quality on touch.facebook.com limited our ability to use modern CSS and JavaScript APIs.
2. Every time we launched a new feature, we had to build it multiple times across different code bases: once for facebook.com, then again for m.facebook.com, touch.facebook.com, and in native applications as well. Honestly, we weren't very good at doing this, so certain features were missing on different devices.

I can summarize these two points very succinctly: the experience sucked. I have seriously high hopes for this new version.

Because the Facebook app for BlackBerry isn't the best (although RIM is working on that), I found myself regularly checking m.facebook.com. Unfortunately, every once in a while I realized that this site wouldn't let me do or see something on Facebook, so I went to touch.facebook.com (there was a link titled Touch Site at the bottom of the mobile site). This frustration would sometimes happen even one more time, and I ended up just having to use the desktop version (there was a link titled Full Site at the bottom of the touch site).

While I doubt this issue will completely go away with this release, I foresee two improvements. One, the mobile site will be significantly better and I will find less of a need to use the full site. Two, I will be able to go straight to the full site if I need to, never having to go to the touch site first.

Facebook is promising that the new m.facebook.com will adjust to your device accordingly, whether you're using a high-end touch device or a feature phone. Furthermore, since every device uses the same framework, the company will be able to develop faster by building new features just once for every mobile device. It also means that everyone can access all of the same features, though they may look different (I will personally test this myself to verify that it's true).

Building for the mobile Web is difficult because you have to plan for thousands of different devices with varying capabilities, screen sizes, keyboards, CSS and JavaScript support, underlying technologies, and browser bugs. The new Facebook mobile site tries to solve this with an UI framework based on XHP, Javelin, and WURFL, a detailed database mapping user agents to device capabilities.

As a result, Facebook can very precisely target experiences and features to thousands of different devices by shifting the focus to building the product and not on supporting device edge cases. Rather than directly writing HTML, CSS, and JavaScript, Facebook product engineers write XHP and use these mobile components to build new features.

On a related note, Facebook took the opportunity today to announce that it now has over 250 million mobile users. That means that a little less than half of its user base uses the mobile version on a monthly basis.

"We think it's important to provide an excellent mobile Web experience," a Facebook spokesperson said in a statement. "Now, whenever we launch new features on the mobile site, they'll be available on any mobile browser, presented in the best possible experience. We're excited to roll out the new m.facebook.com site to everyone over the next few weeks."