How do you know when to give up?
nostrademons: Here's the criteria I used, courtesy of a Sam Altman post (http://news.ycombinator.com/item?id=95883):"If no new or current users/advertisers/customers/etc care about what you're doing, and no one in the company has a plan (or, more commonly I think, a desire) to fix it, you are probably in bad shape."