There were a number of applications/products that were announced or demo'd at Gnomedex. The most noteworthy ones to me were the following:
Mindjet Mindmanager - This was a tool used to document the sessions. I really liked being able to go back to their blog which you can find here to look at the outline of the session and discussion. It would be great if tools like this were used at all conferences. It really was a nice way to review what was said.
Farecast - When should I book one of my many flights? Farecast allows you to do predictive modeling for airfare rates between cities to determine the right time to buy the best priced ticket. Only in Boston and Seattle but coming to you soon.
People Aggregator - Marc Canter unveiled his new meta social networking platform. I played around with it a bit but don't have much real feedback. Conceptually I totally get it and would argue that we embrace the same vision but ultimately it comes down to execution. Is this it? It's not obvious to me right now but it definitely warrants some more time.