Thanks for the suggestions. We are currently discussing internally what level of choice is appropriate for active conversations, and how it should be structured. The current layout is in the realms of the "quick fix".
It's true that the current search facility is not really optimal. Having to know whether you want to search current or archive is a little odd, though also quite common. The fact that "find new messgaes" (i.e. since x time or since I last searched stuff) is on a different page from regular searches is a hangover from when we started out with a third-party bulletin board. When we moved away from it, the people using the board at the time naturally didn't want to see major changes.
We try to bear in mind that a fair number of the people using mumsnet are new to the internet and that some of the terms that are very familiar to web-savvy people can totally flummox people in that position. We try to make our links as few and as self-explanatory as possible. This can make them a little wordy.
Change understandably annoys some people (see this thread ). Also, too much choice can be wearing and confusing and just make people switch off. Take me and BT. I don't care about Option 56 vs Option 57 - I just want a reasonable phone service at a decent price. I have better things to do than update a friends and family list. And frankly I couldn't care less if the electricity comes from the LEB or the Martians.
By the way, you can change the number of results in active conversations by changing the "lastn" parameter in the url to a number up to 200.
As ever, thanks to everyone for all your suggestions. I think we are going to leave things alone now - at least for a time - as we've addressed the original gripes about chat and trading dominating active conversations to the exclusion of other threads.
Regards,
Tech