The Cosmos team (www.cosmosui.org) maintains PartyQuest, which replaces the normal quest log with a much, much better one. It also performs a bunch of communication with other players to track objectives and so forth.

Originally it used Sky for communications, which was horribly intrusive and would break any chat channels that weren't also managed by Sky. That's when I started modifying PartyQuest to work alone, because it is still one of the best questlog replacements out there (the absolute best, in my opinion).

More recently, newer Cosmos developers have replaced Sky with Telepathy to do the same things. It's far less intrusive but still caused problems for me. I was unwilling to give up using PQ, so I've re-modified it to do no communications beyond what the game itself provides in the default quest log (e.g., seeing who else is on a quest, etc).

My sincere thanks to the Cosmos group for continuing to maintain such a sweet questlog addon.