I had a quick add-on thought to my recent post: Eyeballs versus dollars: What should startups focus on?.
The question is:
Are you demographics-focused, or are you activity-focused?
If you are demographics focused, then you are taking a cohesive group like 30-40 year old parents and providing a wide collection of services to them. Obviously you have things like forums, messaging, social networking, etc., but you also have vertical apps that help you book travel or do things specifically for that demo.
If you are activity focused, you are trying to take an activity like travel, and providing the best functionality regardless of the audience that’s using it.
Both approaches can be successful, but it’s an important choice to figure out what your site is all about.