Maybe ads. Maybe it is finance supported by virtual capital. They don't make and want to make money at present . I heard news rumour google have plan to acquire bookmarking site and url shorten site like tinyurl .
Do not know. Just an idea, they can easily rank the links they are storing. These can be a high accurately measurable source for advertising companies.
adsense !!! nope.. they would be earning nothing from it... tinyurls are redirected without going to their site
well i guess they online earn from the homepage when users visit it to make shorter urls. Normally 2 impressions per user, one homepage the other is the page with the shortened url.
When you go to their site to create a redirect there are ads. There is very little bandwidth involved in redirecting.
Every click provides information for data mining purposes. So in addition to front end advertising there are people/companies willing to buy the information gained from what is being clicked on, by whom, and where the traffic is coming and going. So there are probably many ways they can profit that are transparent to the end user.
They run ads, but if you have the kind of traffic they do you don't have to be making money to stay afloat as a business. The potential value of the traffic keeps you going.
Every time when you require link cloacking you've to visit their website means it increase their views and popularity, also the site attract advertisers and increase chances of click on adsense ads. Not sure they might be generating revenues from the links that serve for particular affiliate.
Even if they earned nothing, the website would have good value if it was up for sale due to it's popularity and renown. I'm sure the website brings it's owner and his other websites some popularity and traffic and business. It's not all about the money. http://www.gilby.com/about.html
Maybe they also have a script which checks all the links submitted for error 404s and then redirect those old tinyurls to their own page with ads on.