The pager is currently capable of sending popup balloons to its users, but does this rarely.
Messages about friends logging in (not out), friends playing/joining games, and about replies to forum posts should be displayed in such balloons (with an option to toggle them). Clicking on said balloons should react intelligently: Clicking on a forum response alert should open the link to that response. Clicking on a friend's log in alert should begin an intuitive chat with that user.
If I'm not mistaken, the pager currently only pops up to alert you that new games are online, and I don't believe clicking on these popups does anything intuitive?
* Steam provides an excellent example for game distribution mediums.