Is Facebook the mobile web's killer app?

Active users of Facebook's various mobile products has grown from 5 million to 15 million since the beginning of the year, says the company. In particular, the ability for users to not only update their 'status' while on the go but also to comment on their friends' updates, has spurred mobile use of the site.

"When we recently added the ability to comment on your friends' status updates to the Facebook mobile site, we didn't expect that we would receive nearly a million status comments in the first 24 hours", writes Facebook's Wayne Chang on the company's official blog.

While that particular tidbit is interesting, it should be no surprise that mobile versions of Facebook are proving popular. Not when you take into account that Facebook offers two browser-based mobile versions of the site -- one for low-end feature phones and another for 'smart phones' -- as well as native Facebook clients for Blackberry, Palm and iPhone. Notably, the Palm version runs on the smartphone maker's entry level consumer offering, the popular and affordable Centro. While television ad campaigns that aim to push the Blackberry beyond its business roots and into the hands of consumers pitch Facebook access as a major selling point. Ditto some of the most recent ad campaigns for Apple's iPhone.

See also: BlueWhaleMail: Facebook messages “pushed” to your cellphone

And it's not just high end smartphones that are getting their own Facebook client application.  As I wrote over at last100, a new low cost cellphone that puts Facebook and other social applications at its center will debut this week on Hutchinson-owned 3 in the UK and Australia. The new handset has been designed by another Hutchinson subsidiary, INQ Mobile, and is the first of a number of “low cost social mobile” offerings in the pipeline. INQ has been working directly with Facebook in order to offer better integration than is available on existing low end handsets.

Handset makers clearly see Facebook as a way to sell more phones but what's in it for the carriers? Aside from picking up or retaining subscribers, the telcos hope to get more people using the mobile web in order to sell more data.

“For 85 percent of our customers, we can’t really sell more than voice and text,” INQ Mobile’s CEO, Frank Meehan, told Unstrung. “You need to drive data usage higher right across all the handset segments. You want the majority of customers, not the top-end of the community that rules strategy at the moment."

See also: Snap2Face: Facebook lands on Windows Mobile