Instant Messaging

I have used numerous instant messaging softwares and I have to say they all are really cool and easy to use. I first used AOL Instant Messenger, or AIM, and loved it. I used it to communicate with my friends throughout middle school and high school, as well as during college. It does put some restrictions on things like random people trying to add you, for the most part. It allowed you to personalize it, do file transfers, speak through microphones, and I think even video chat. It has been years since I last used this mainly because Facebook started up their own instant messaging and made it more convenient to talk to all of your friends.
If I'm using any instant messaging service now at all it would be the Facebook chat. I like it because it's in your Facebook browser window and makes it a lot easier to talk to people while you multi-task. One downside to it is that you can't actually personalize it AND if you just don't want to talk to someone you have to go offline of the chat completely instead of just blocking users. Geez, it may have changed since I rarely use that these days.
I also used MSN Messenger and really liked it because you can do more with it in terms of personalizing and multi-tasking. For example, you can play games with people through it, you can send them cute short animations, it detects what music you are listening to, and my favorites, allowing larger, personal pictures as an icon, and sending 'nudges'. Nudges are sent person to person and it shakes the screen like someone nudged you. I didn't use this as much because I didn't have many friends on MSN, most of my Texas friends were on AIM, whereas my friends and family in Illinois were mostly on MSN. With Facebook developing Facebook chat, it eliminated the need for me to use MSN.
The other software I used was Yahoo! Instant Messenger and I used it to talk to one friend then convinced her to get AIM because I was tired of random people trying to message me and add me.
Lastly, I think instant messaging is a very convenient tool for communication even for libraries as it would be easier for librarians to communicate help to patrons from their desk instead of having to leave their desk empty to help someone which could take a while.