You should only consider an extension other than .com if you can get a significantly better exact match domain than in .com. .net and .org rank well in search engines also, and having an exact match domain in either of them would work better than a .com that isn't exact match. That said, for a gossip website, you're targeting the mainstream crowd and using something other than a .com would hurt more than usual, so stick with a .com even if there's a nice keyword .net or .org.
Depends on the concept you have in mind... If your going for BRAND I would recommend getting the .net and .org and probably a few others. If your building a few affiliate websites or other small concepts I wouldn't bother. Basically, If you feel that someone could confuse your brand / visitors and you need that trust then get several extensions. However, If you ever decide to copyright your product/brand in the future then the owners of the other extensions won't be able to provide similar services anyway.
.com is oldest domain name after that .net come in the market that way the domain name stands is define on the basis of .com and every user move first at .com and pronunciation after that any others...
I will always choose .com... it's like my primary choice.. if really can't get it, I will either choose .info or .net
.com is still what most inexperienced internet users go to anyway. LOL I know some people who think everything is .com
obviously .com is better then .net in terms of standard domain name. If you promote it(.net) in search engine you have to do a lot of stuff and more affords then .com.
Be professional and I have 5 years experience in spending other than gTLDs they all suck in front of .com. Buy killer domain and start up with awesome website.