My friend is kind of a patent attorney. He just got back from BarCamp Orlando (350 strong!). When he and I discuss Web 2.0, the one thing lacking is IP protection. Sure, everyone uses distributed computing in clouds and clusters, but no one stops to think about Intellectual Property rights.
It is more than just the ownership of the idea for something like Flurl or Vidoop. IP means licensing and asset management. There is a legal opinion that you shouldn't patent unless you can afford to defend it. The opposing opinion is to patent your idea so you legally own it.
When you look at the thousands of VOIP related patents, you know which way that sector went. It just seems like when web app dev is being discussed, IP isn't.
The other pitfall to this is Who Owns the Data? Lots of apps are moving to SAAS (software-as-a-service), where the data is kept on a 3rd-party cluster. How does Privacy work in that distributed model? Who is responsible for a security breach? These are factors that need to be considered as we expect SAAS to go mainstream. No business which owns licenses for, say, accounting software or Office is going to move to a web application that is not patent pending and without a clear delineation of privacy, ownership, and archive. These are just some things to think about when starting a business or application development.