• by Erik Sass , Staff Writer @eriksass1, March 9, 2010

Recently I saw more data documenting increasing use of mobile devices to access social networks. This time around the data is from comScore, which found that the number of visits to Facebook via mobile browsers increased 112% over the last year, while visits to Twitter via mobile devices increased 347%. In terms of raw numbers, these figures represent an increase from 11.8 million mobile access users in January 2009 to 25.1 million in January 2010 for Facebook, and an increase from 1 million to 4.7 million for Twitter over the same period.

Clearly mobi-social networking is appealing to the tech-savvy, on-the-go demographics that dominate social networks and smartphone adoption. But what about the advertising? Setting aside the fact that both networks are still tweaking their ad models, I'm wondering how they can handle the challenge of delivering ads to users on mobile devices -- specifically, how they will address the basic issue of visibility.

The screen sizes of Blackberry devices range from about 2.4 inches to 3.25 inches, measured on the diagonal, while the iPhone's screen measures about 3.5 inches on the diagonal, yielding total screen areas ranging from 5-10 square inches for smart phones in general. It's one thing to imagine delivering display or search results alongside content when the user is engaged in mostly passive consumption of media, but in the more interactive context of social networking, this is not a whole lot of space to work with, especially on the iPhone, where the screen is also the sole interface.

Now, I will admit I am basing this judgment on my personal experience. For some reason my fingers just seem to be more stubby and awkward than other people's, so I find smart phone interfaces (both touch screen and key pad) hard to use to begin with; if I try to compose an email or send a message on a social network, I end up looking like a bear trying to change a watch battery. But even my more nimble, dexterous peers confess the smart phone interfaces sometimes give them trouble too, especially during high-interactivity tasks.

One possibility that various mobile media distributors have been experimenting with is the roadblock ad, which could appear before the social network session, leaving the rest of the interface ad-free. Obviously roadblock ads are kind of annoying, but is there a better option out there? One thing's for sure: if people start feeling that ads are crowding out their mobile access to social networking, you risk a backlash against both the social networks and any advertiser who commits this blunder.