PALO ALTO, California: Some 65 million people around the world now regularly access Facebook, the social networking portal, via their mobile phone, a total that has increased from just 20 million eight months ago.

It has been argued that social media is likely to enjoy the highest rate of adspend growth among all the various digital channels over the next five years, with mobile advertising revenues similarly set to register a sizeable uptick on this measure.

Speaking at the recent ad:Tech Chicago Conference 2009, Rishad Tobaccowala, of VivaKi, also predicted that the rising importance of "mobility", exemplified by, but not exclusive to, cellphones and PDAs, will be a key factor encouraging this trend.

Facebook Mobile was originally launched in 2006, and was initially only available in English, and with a limited range of features, but has since been radically updated and translated into a number of different languages.

The company is now operating one mobile site for all web-enabled cellphones, and one for smartphones such as Google's Android, Apple's iPhone, and devices manufactured by Palm and Nokia.

Writing on a company blog, Henri Moissinac said that its members are able to "update your status, browse your News Feed and your friends' Profiles, comment or 'like' stories, and view or update your Facebook Page" on their phones.

Late last week, the Palo Alto-based portal also made Facebook Connect, which allows consumers to sign-in to a variety of web platforms using their log-in details from the social network, active for people using the mobile internet.

It has previously developed a text messaging system that enabled users to receive "notifications", update their status on the website and send and receive messages via SMS, and which is available through 52 different operators in 25 countries.

Data sourced from Facebook; additional content by WARC staff