Now that I've been added to Planet Debian I've been thinking about the ways I've been communicating through the years on the Internet and I've seen that it has changed a lot.
I started to use email back in 1992 or 1993, and at that time I used to read Usenet news and subscribe to mailing lists. I don't know why, but I never used IRC back then and later it seemed kind of childish, probably because the people I knew that used it was childish.
After 1995 or 1996 I started to leave Usenet and moved to mailing lists. I used to think that they were the only medium I'll ever need to work with other people in a project, but now I feel that, being still useful, they are not as good as they used to, mainly because SPAM and also because I'm subscribed to a lot of Debian lists ;)
In 2000 I started to use IM systems, mainly because it is a lot faster than e-mail in a lot of situations (i.e. to speed up communication with people that worked with me) and because a lot of people asked me to use them ... a good side effect of this is that I'm in touch with a lot of ex-coworkers using IM systems, I've moved from company to company but usually I don't delete friends from my contact lists.
In fact, I still use IM systems today (we have installed a private jabber server at the office), I believe that they are one of the best tools for P2P communications and can be very useful (I've written more than two reports using the log of a IM conversation).
Lately I've begun to use IRC and I have to say that it is much better than I thought, probably because I'm connecting to specialized channels that are very useful to work on Free Software Projects and allow groups of people to solve problems or simply discuss things in real time, without the email latencies.
And last but not least, we have the web based systems: web forums like Slashdot, Barrapunto or Puntbarra that are very good to exchange news and talk about things without having to use the e-mail or blogs and aggregators like Planet that let people rant about almost anything and have dialogues in an indirect manner.
Let's see how good it is.