Different people have different opinions on the whole Fora (forums) vs. mailing lists vs. newsgroups thing. Here I lay out my reasons.
Fora
- Have topic and sub-topic groups.
Mailing Lists
- Archived off-line.
- Archived on-line, often.
- Real "From" contacts (i.e. can look up people in your address book, etc.).
- Real threading (usually; some lists fuck this up).
- Individual message "read" state.
Newsgroups
- Full tree hierarchy of topics.
- Archived off-line, if configured.
- Archived on-line, for most public groups.
- Real "From" contacts (i.e. can look up people in your address book, etc.).
- Real threading.
- Individual message "read" state.
- Ignore and watching of threads.
- Subscription is all done in the client, and thus more reliable.
Now, before you get all flaming toasty on my arse, I will point out that not all these points are always restricted to the items I've put them under. For example, some fora do do 'real' threading, but I've yet to see one that does it as well as an off-line client.
The Result
As you can see, I rate both mailing lists and newsgroups much better than fora. It's a bit of a toss-up which of those two win, though I prefer newsgroups for discussion (pull), and mailing lists for notifications (push) generally.