I'd be interested in finding out why investors dislike productivity software so much.

In my experience it can be hard to sell -- you're often stuck explaining to someone why they suck at their job.

Unfortunately, I don't have hard data on it. But my guess is that there are two issues from a business perspective:

1) Productivity software is not something that is likely to spread rapidly (and cheaply) like a social network or a game. Unless you can pull off something new and clever, it's likely you'll need to pay for users. 2) It's tough to make it monetize well: it isn't something big companies tend to pay for, and it's still relatively unusual for individuals to pay for it.

That's a tough combination. May change, but I can see why investors are skeptical.

I suspect developers also tend to be familiar with productivity software; Most everyone has used an issue tracker of some kind while writing software, so we think we can do better. You end up stuck in the workflow-software quagmire, though: everyone works slightly differently, so to support everyone you need to get so abstract that it's not useful.