We use hackpad at sendhub all day, everyday. It's invaluable. I've used other wiki systems like atlassian and wiki media but this is the only that's stuck. Easy to use, updates in realtime and the founders have always been available to listen to and respond to our feedback.
I use HackPad and really love it. Some things can still be improved, particularly around knowing what functionality is available. But overall this is super useful and i love the simplicity.
Founders, any new features you're planning on rolling out soon?
I was surprised to see my Google contacts in the autocomplete. I thought I'd just used it for login. I guess even I can't be trusted to read the OAuth notices. (Google should really turn theirs up a notch, but still...)
Well done Alex and crew!