In addition, once you subscribe to a mailing list, all info comes to you. No password necessary. Read, reply, lightning quick.
Contrast this with forums, where you have to remember to go out to each and every forum you're interested in, put in the password, and then operate within the work-flow of the forum.
I'm subscribed to mailing lists of 20 LUGs. Can you imagine the inconvenience if I had to go out to each one and put in a password just to see if there's anything new? With mailing lists, the information comes to you, instead of making you go out to it.
This is exactly my thought on the subject, but phrased better that I could have done it. I don't mind an "archive" web site which records all of the emails. And it it properly threads them, that is even better. I have that on a number of my lists. And you can even post through them. The post goes directly to the web site, which then "fakes up" an "email" which looks like it came in via the regular email channel and sends it back out via the normal email channel. But there are some which don't do this "echoing". In those, I end up just ignoring people because it is too difficult for me to bother with going to the site to reply.