For someone who's not familiar with the app, I have to do a lot of decoding of your home page to figure out what exactly the product is and why I should be interested.

Your /tour "Features" page explains it much better:

"TEAM INBOX & CHAT Replace IRC, IM or Skype chat with Flowdock."

That's something I can quickly parse and immediately understand.

I also echo the sentiment that more screenshots (hopefully with call-outs/highlights) would probably help out.