Back in October 2007, Microsoft (Nasdaq:MSFT) announced a $240 million investment in the upstart social-networking company Facebook. There was instant skepticism — after all, the valuation was a whopping $15 billion. And wasn’t MySpace the dominant player in the industry?

Things can change fast in social media. Now, an IPO is imminent for Facebook, which could fetch a valuation over $100 billion. Microsoft’s investment certainly looks prescient, and the deal also provided the company with insights into social networking, as well as a platform for its ad network.

But does Microsoft want more? It probably does. Just look at Google’s (Nasdaq:GOOG) new social network, Google+. In just a few weeks, it has attracted 10 million users and has been a nice driver for the stock price.

It seems like an interesting coincidence that a Microsoft-backed social site, socl.com, popped up last week (this was according to a report from Fusible.com). However, the site was quickly taken down — apparently, it was accidentally deployed by the Microsoft Research team.

The focus of the site is still vague. But there were logins for Facebook and Twitter, and the service had an interesting name: Tulalip.

This has brought a lot of speculation. Perhaps the big play is to integrate more social capabilities into Microsoft’s Bing search service — actually, this may be a necessity.

But there are other possibilities. For example, Microsoft could make its Office 365 service a social platform, which could pose a threat to Salesforce.com’s

(NYSE:CRM) Chatter service.

Or maybe Microsoft could use its incredible gaming technologies. Might the company build a rival to Zynga?

Microsoft has incredible potential in this sector, but the problem, unfortunately, is that the company continues to be slow-moving. Not only has it lagged social networking, but also mobile applications and the cloud.

For shareholders, it is probably better to wait and see how Microsoft’s strategy takes shape. But based on the company’s actions over the years, it’s not easy to be optimistic.

Tom Taulli’s latest book is “All About Short Selling” and he has an upcoming book called “All About Commodities.” You can find him at Twitter account @ttaulli. He does not own a position in any of the stocks named here.