When it comes to branding on the internet, the single most important thing is your domain name. I don't point that out in a cavalier manner either, from type-in traffic to perceived authority in the search engines, you're domain name could spell the success or death of your project.
There's also a big difference from owning the ".net" to owning the ".com" domains. People around the globe are so trained to type in ".com" after a brand name, that when they get a site that's a parked domain with ads on it they become seriously frustrated and their impression of the brand can be affected. They likely would never try the brand name with ".net" or ".org" or ".info", 9 times out of 10 they give up.
Topix, the online news service, realized that this week. PaidContent is reporting that the owners of Topix, (Gannett, McClatchy and Tribune) have paid over $1 Million for the ".com" version of their name. Previously everything was on the ".net" version. Now they also have concerns about loosing their ranking with the search engines, hopefully they'll have smart webmasters who know how to correctly apply a redirect (301 it rather than 302).
The Topix example demonstrates the marketing and business thinking that needs to go into launching a web product. Unless you want to strictly focus on a tech market, where customers would be more likely to type in the ".net" if they don't find you on the ".com", or your total branding focused on the fact you were ".net", acquiring the ".com" version of your brand is essential.
With the occurrence of cyberquatting on the rise, it's more important than ever to acquire and secure your domain name. Doing that before any word of your project leaks is even more important. Opportunists lie in wait for those bad business decisions, to scoop up those domain names that business so foolishly didn't.
Even if you have to sit on that domain name for months before the project launches, register it, and get some kind of branding started by putting up a "coming soon" page. Not only does that eliminate the potential threat of cybersquatting, but it might give you a lead on the domain aging before the project launches. If you are considering several names for your project - register all of them. At $7.95 a year, you certainly can afford to. Otherwise, not registering the domain name could end up costing you millions, just ask Topix about that.