Why I prefer modern instant messaging over the old way
Above is how people used to do instant messaging. What you see above is an AOL Instant Messenger 5.9 chat window. I have a virtual installation of Windows 98 in my VMWare and installed the old 5.9 client just so I could show you what it looks like.
There are some people who get all sorts of nostalgic over AOL Instant Messenger, commonly referred to as AIM. Mention AIM to anyone who was using internet in the late 90s or early 2000s and chances are that person who go on about how the "internet used to be better" back then and so on.
Old-style instant messaging is for all intents and purposes dead as a doorknob. However, IM itself didn't die. It just evolved into something else and got slightly slower.
Modern IM is SMS (cell phone texting) and Twitter. Both platforms are designed for short messages. SMS is user-to-user, and Twitter can be public or user-to-user using the "direct message" feature.
If you want to get really technical about it, SMS and Twitter isn't "true" instant messaging and acts more like email. However, if you asked anyone whether they'd consider those messaging platforms IM or email, they'd probably say IM first. Or to be more specific, they'd call it "slow instant messaging".
The thing that all the old-school IM fans gloss over is that IM via use of AIM, Yahoo! Messenger or MSN did kinda suck. A lot.
AIM in particular was ridiculously invasive for a while. You'd be on your computer doing something like writing an email or reading a web page and blammo, there's a new IM window right in your face. Yes, the chat window actually purposely launched directly in front of whatever you were doing. And for the life of the old AIM client, they never really fixed this issue.
Y! Messenger (YIM) and MSN were bad also, but for different reasons.
YIM was plagued with hackers who exploited the client left and right with "script kiddie" b.s. where they'd find some random user (maybe you that day), crapflood your client and crash it, usually along with Windows itself.
MSN held the "honor" of being the biggest (it took up a lot of screen real estate), chunkiest, slowest piece of crap you ever saw as far as an IM client was concerned. It was unbelievable how much memory MSN sucked up when in use. Another "honor" MSN had is that it was the first one to have IM spam, which some called SPIM.
Oh, and let's not forget ICQ. Almost forgot that one.
ICQ was the first IM most people used in the 90s, yours truly included. And it was plagued with problems as well. App stability problems, hacker problems, etc. Everything bad that could possibly happen with IM happened in ICQ. In fact it got so bad that it was a reason people jumped over to AIM, YIM and MSN.
The only "true" IM left that some people use is Facebook chat. Most use it in the browser, but there is also an actual installable client that exists for it, similar to MySpaceIM when that was around.
My suggestion for anyone that wants IM is to use Twitter. Either launch a tab in a browser and use it that way, or for little sound notifications, TweetDeck (owned by Twitter) does have that. It is the best way to do IM these days, even if "slow".