One notable thing about today’s major social media brands — Facebook, MySpace and others — is that they worked their way up to become giant web presences on their own. Imagini, a startup based in the United Kingdom, would rather hedge its bets with a brand partnership with Pepsi, just announced this morning.

Imagini is the parent company of Youniverse, a site that currently consists of nothing more than a few picture-based personality quizzes and some simple social networking tools. Youniverse is so simple, in fact, that it comes across more like an application than a social network.

Pepsi’s version of the site isn’t much more complicated. Centered around six major football (or soccer, in our parlance) stars like David Beckham, the site offers a way for fans to compare themselves to their idols and each other. Pepsi will also run a global ad campaign to promote the brand site.

Despite its bare-bones simplicity, two things are apparent with Imagini. One is that the company plans on entering more partnerships as the year goes on (the press release makes note of upcoming campaigns for music and “hopes and dreams”). The other is that it plans on expanding its networking capabilities and becoming a destination site.

Founder Alex Willcock was cagey about his plans when I interviewed him, but did say that eventually Imagini’s sites “will be a place you’ll come to have fun and be entertained.” It appears that the company plans to slowly add on features while entering more partnerships, spreading its name to a global audience and over time becoming a social networking destination.

Because it’s simple, easy to use and visually-based, Imagini looks like a great platform for brand campaigns (obviously, Pepsi thinks so too). Its partnerships should easily net the company a lot more users than the five or six million who have so far visited the main Imagini site. The question is, for all the traffic it gets, will Imagini be able to compete with the existing social networking powerhouses? See below for a screenshot of a Youniverse profile.