Yeah, there are quite a few notable startups and a strong community that is growing very quickly. Just had Startup Weekend in Orange County with another planned for March and one in LA in January.

Some solid Tech Meetups: - OC: http://www.meetup.com/OC-Tech-Startup/ - LA: http://www.meetup.com/Los-Angeles-Lean-Startup-Circle/ - SD: http://www.meetup.com/SanDiego-Tech-Founders/

I'm down in Orange County so I'm more involved in the community here with startups such as Mavenlink, Catchfree, and Drumbi. If you're going through LA, I strongly suggest stopping by Coloft.

If you have more questions or anything, let me know.

Grubwithus.com is based in Venice beach

We're not at all "notable" amongst the startup scenesters, but Ties.com/Scarves.com is located in north Orange County.