I have to ask....... is this really a feature that people use and/or like? Maybe I'm showing myself to be an old fogie, but - honeslty, why the heck would anyone want that?
/honest confusion
In a game powered by Gamebryo it's a godsend. Fallout 3 will NOT tab back in. So if I want to wiki something I've found to figure out just what the hell it is, or if I need a hint with a quest, I can just hit shift+tab, browse to the wiki and have a go. Or if I want to listen to a certain song for a battle or something I can go to Youtube and play it.
The in-game browser has to be one of my favorite Steam features.
Steam IM is another biggie. ALL of my online friends contact me through it. I can chat with them from within game, without alt-tabbing and risking a game crash. Another pretty awesome feature if you ask me.