http://www.livejournal.com/support/faqbrowse.bml?faqid=158 is exclusively about downloadable clients, and the clients page is also exclusively for downloadable clients, so I think it would be possibly simpler to create a new FAQ about online/web-based (what is the preferred term?) clients.
This would include:
- disclaimers about giving one's password to other parties (and indeed, if I recall correctly, my twitter import client uses a hash of my password rather than the password itself)
- the rather more secure use of post-by-email in some web clients and its settings and requirements (not a free account)
- the fact that anything making automated entries can annoy those who read your journal (anti-Twitter-import feeling is strong enough I wouldn't feel right about documenting it without making at least a passing acknowledgment)
- while one can usually be assured that a downloaded client will continue to work unless LJ changes its interface, no matter if the creator disappears in the night, there are no such assurances about a web-based client unless one has a copy of the script and is hosting it one's own self