Imo is the instant messaging service for you if you want to keep track of your friends on all networks. Connect with people from MSN, Yahoo, Gtalk and AIM for instance. This app also provides you with webcam support, and you can use it right online or on your desktop on just about any device. If you need a simple solution for your video conferencing, this app can provide you that as well.
It is a simple interface, and it does not take up much space on whatever device you use it. It also probably would not slow down your browsing as much as more complex apps would. The downside, however, is it does not have emoticons, customized fonts or other advanced formatting support. Still, it works well for fast communication.