Two things I've found incredibly useful on other websites, and they would make very useful additions here, if you could find a way to make them viable!
1) Cumulative quotes.
Below each post on NaNo, is quote button - but hitting it takes you to "create a new post". More than once I've wanted to quote more than one post in a thread, and I doubt I'm the only one! I've often seen 3 or 4 posts by the same user, back to back, because they've been quoting people.
On two forums I've seen (both hosted by Invision, if that's any help), hitting the Quote button below a post turns the button red, signifying that it's been marked. You do this for as many as you want to quote. Then when you hit "Add reply", each post you clicked "quote" for appears all in the box for you to type your reply. If you find you clicked "quote" in error, clicking it again will de-quote it.
It would save the multiple posts thing, and keep thread sizes down - and that'd be helpful for everyone!
2) Bookmarking favourite threads.
I know you could bookmark the URL and stuff, but that won't show updates. On another forum I used to use, any threads that you flagged as "favourite", appeared in a list on your control panel. It was incredibly useful, because at a glance, you could see all the threads in one place (and the little icon next to the thread title showed you if there was a new post or not). Also, it had a list of which friends were online right then (you could click a link to take you to your list of all your friends, but there was a box to see just those online).
I could PM the URLs to an example of both websites, if that'd help (register to make an account and then see the things in action, if you wanted).
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BFS goals - http://www.nanowrimo.org/eng/node/1075131
