I'd have to agree, training on the Twitter API is just a bad idea. Its just weird to see a company do everything imaginable to drive people off their API to turn around and want to train people on it.

Most companies turn kind of hostile with their API when money is at stake but Twitter has been particularly bad, especially considering a lot of the innovation on their platform happened on third party clients. They haven't mustered any kind of innovation of their own either.

The Chinese weibo's like Sina are actually quite a bit more interesting if you can deal with the language and the governmental interference.

If you want a ground floor learning experience app.net is probably a better choice though I doubt its ever going to gain critical mass.