One reason I like Skype is because it does not seem to have the big "footprint" that so many of Microsoft's products have. In other words it does not take up so many resources of your computer. It works well, and has good features to remember chat histories. The only other one I use is Yahoo Messenger, but I use the one on the web, so I do not have to install it locally. It works fine, but I still prefer Skype. Also Skype does not do the "heavy-handed" approach of ushering you down a certain path or their choosing. It seems to respect your volition more than Microsoft does.