Facebook is said to be working on a mobile advertising product that it could launch by the end of March 2012.

Insiders report that this could involve putting Sponsored Stories ads, which feature friends’ interactions with brands, within the mobile newsfeed.

This stems from a report on Bloomberg last night, itself based on a conversation with two unnamed informants from within the company.

Since mobile adspend is predicted to reach over $1bn this year, and grow to $4.4bn by 2015 according to eMarketer, this could create a healthy additional revenue stream ahead of a suspected IPO from Facebook next year.

Bloomberg says that Facebook expects its next 1bn users to come largely from mobile devices, rather than desktop computers – and more than 350m users already log-in via their mobiles.

Though Facebook obviously recognises the potential in mobile, Deals and Places weren’t successful in engaging users through this channel.

Google and Apple might have led the way in this area, but for advertisers mobile is still relatively new ground. They’re still unsure of how to approach the balance between useful and intrusive, and that’s something that Facebook could use to differentiate themselves by handholding businesses through the process.

Just as it is on the Web, the social network is in a prime position to roll out highly personalised and targeted ads because it has so much information to hand about a person’s likes, dislikes and interactions. This could ensure relevancy, and ensure that appropriate ads are being served at the right time to the right people.