We operate a good sized, and rather popular Intranet. The site is updated daily with articles or other info. Our employees use it extensively to locate a wide variety of information. We are not huge, but not "mom & pop" etither. About 700 people, all under one roof.
I have read that many large companies are creating a "myspace" like environment within their Intranet, a super-charged employee directory one article called it. Even here, in the Intranet Journal there is an article suggesting to implement one as a way to entice employees to use the site.
My boss & I both agree it would be something fun to do, but at the same time we both also wonder if that's all it would be - fun. If we already have a strong following, what's the justification?