Xfire used to be my instant messaging system of choice. This habit originated when I used to use other IM programs, which would minimize the game that I was playing, with all sorts of problems that would come with staying defenceless in one place for a while. Even worse, the trivial message could even take my computer 5 mins to recover, especially if the game came from Steam. But then I got Xfire and quickly convinced my friends to run Xfire aswell, mainly for playing with each other.
But Xfire is rather stale, support for other IM systems used to be run by another program (and now by an alpha feature) and anything besides my PC doesn't exist according to Xfire. Which is a shame, because most of my gaming doesn't happen on my laptop anymore. That era ended a long time ago. All I play on it is MTGO and TF2.

When my little brother got a Razer Naga for his birthday, a small flyer for
Raptr came with it. On the flyer they had the cheesiest comic ever, to show what Raptr can do. For the ones that don't know Raptr, it's an IM and community system built around the fact that gamers just might have more to play on than a PC. But at the time, I didn't feel any need to switch, so we threw it out.
But recently, I found one of my old friends using Raptr. A flyer isn't enough incentive, but that friend was. I was quickly sold. You see, I do not like any clutter on my computer. Mainly because I am far to lazy to clean up anyway, so less programs = less hassle. That's why I used programs such as Miranda to reduce the amount of IM programs.
Raptr does the same, accepting AIM, MSN, Yahoo!, ICQ, Xfire and so on, while still keeping Xfire's greatest upside: In-game chat.
But that isn't all. Raptr also supports tracking for your games, just like Xfire. But again, it tracks more. Raptr tracks games played on PC, Xbox, Playstation and also tracks a wide array of flash games. And if you are a tad more retro than that, you can manually add your games from about all consoles, like the SNES or NES.
In short: Raptr watches you game.
Raptr also mimics Xfire by having a profile page for you, but extends this to a live feed, keeping people updated on what you play. And again, it does far more. All of the games you own or play can be added to your library, which quickly ends up being a gigantic list (over 125 games for me already, and haven't even added all of my games), neatly sorted by platform.
You can also write reviews for your games, in addition to a 5-star based ranking system. Unfortunately, it's hard not to be reminded that you are on the internet, where stupid people lurk. Apparently, Need for Speed started with street racing, there were no titles prior to NsF:Underground.
Still, that isn't all. Each platform has it's own features that come with them. Trophies on PS3, friend-codes on Wii and DS and Achievements on the 360 and Steam. There is place for all of them. Where xbox.com only compares two people, Raptr can compare 4 people, whether you want to see Steam, Xbox, PS3 or even WoW achievements. Raptr's great strength lies in the details. It simply packages lots of services and stores them in one convenient place.
But are there any downsides? Ofcourse there are. Raptr isn't exactly a velociraptr. It took about a week before it had found all of my achievements and games. It might have taken longer if I hadn't posted in the "Raptr can't find my XBL/PSN/Steam/underwear"-threads.
Another downside is that if you use MSN and Xfire, you might have duplicate friends. Bear in mind that Raptr only takes your contacts from each IM service and simply shows the online ones, grouped by service.
So yeah, it's a bit rough around the edges. But what do you expect from a beta?
P.S.: Have I mentioned it's Facebook/Twitter support? Even the 360 itself is compatible now.