When we spoke to him at CES today (more on that later) Greenberg told us "I can't commit to when that will happen, but that is something we want to do. It's definitely something we're looking at expanding and, as this social network grows, we've absolutely heard the pleas for that. It's on the list."
Greenberg explained that original Xbox games were coded to be limited to 100 friends, and that limit was brought into the current generation. But now that Live is built in to the system, they've got a little more flexibility. We, and the thousands of potential friends we turn away daily, can't wait to hear more.