you can learn from the backlash seen from YouTube and Facebook users who felt cheated when the sites built a loyal userbase, got bought out and suddenly the user experience drops in favour of advertising revenue. After all, without a userbase, there would have been no aquisition, and no investment to recoup. So I predict (and hope) that 2008 startups will be wise to this, and keep user loyalty in the long-run by working unobtrusive revenue models into the site from day one.