I recently became an Insider on ESPN.com. So far I think my favorite thing to do with it is comment on stories on the website.
A few weeks ago I posted a question about Peyton Manning in "response" to an online article, then got excited because two people actually answered.
Other things I've done so far as an ESPN Insider include setting up my favorite sports, teams, and players. My favorite sports are NFL Football, MLB Baseball, and NCAA Football, and now that I've named them on ESPN.com, they're listed underneath the score banner near the top of the web page when I sign in to my account.
I named the New York Giants and Yankees as my favorite teams, and of course it follows that among my favorite players are Eli Manning, Justin Tuck, CC Sabathia, Derek Jeter, and Curtis Granderson.
The thing I'm not sure about though is exactly how useful all of this can be. If I have the chance, I'll pay around with Insider a little more and do another post on it and the usefulness of its features.