At USV, we talk a lot about how the landscape is changing, as more entrepreneurs and investors get behind the idea of building networks around problems, communities & verticals.  And that means that we are seeing more competitors in each space we look at, especially compared to what it looked like when USV invested in tumblr, etsy etc. (i.e., the halcyon days of yore) I have a suspicion that -- while this is no doubt true -- that there was more competition around these ideas than we remember, especially because many competitors fell off as the leaders emerged, so we don't remember them anymore. It would make for a neat research project to look at modern-day category leaders across a bunch of categories, and map them back to the competitors around them at various times in their history.  Funding milestones would be an easy way to do this. Does any such thing exist?  Seems like something that could be done relatively easily using the Crunchbase API.