Behind the scenes: 37Signals's Haystack
37signals.com
37signals.com
It's not as huge a gap as with Haystack, to be sure, but anyone who's tried to get non-webhead clients to grok/use Basecamp will know what a struggle it can sometimes be. People have been asking for years for the app to have more help/guidance that's geared towards client end-users, rather than the agency account owner.
As for Haystack, I sort of see it as a (reverse) extension of their job boards, which seems to have been pretty successful for them despite not being something they themselves use very often.
I wonder how much they paid for the domain?