All I can think of is a subscription-based model that would aggregate all of the URLs and give you stats on it. Like, $5/mo for a URL shortener that lets you see how much something has been clicked on, who clicked, when, and so on. This would also serve as a history of shortened URLs.
But really something like this is probably best rolled into the services that require them, like Twitter. Twitter should provide it, I think.
Models that are based on "hope I get bought out" are not viable imo. All business plans are obviously dependent on certain favorable conditions (like finding customers), but it's a lot easier to find some customers than it is to convince one of the very few potential acquirers to first acquire a business that provides your functions and then second to acquire you instead of a competitor.
Absolutely. I was being at least partly sarcastic here ;)
The funny thing about bit.ly is that they take this model to the next level - they are actually building to be bought by a specific company which has yet to make any income itself.
On the other hand, bit.ly's investors have a lot of pull in Twitter, so it's a unique situation. I don't know enough about VC investments to tell, but the situation where investors in X create Y in order for it to be bought by X - obviously with some profit - is pretty interesting.
But really something like this is probably best rolled into the services that require them, like Twitter. Twitter should provide it, I think.