HelpSpot is indirectly mentioned in 37Signals Getting Real book. I was reading it on the plane home from eTech when much to my surprise on page 148 I see a half page quote by David Greiner of Campaign Monitor. The quote is in the customer service chapter of the book and he's talking about how he and the other founder do all the support and how it keeps them close to the customers needs an so on. Of course I know that it's HelpSpot they're using to do it! Pretty cool. Now if I can just get HelpSpot in the book :-)