The current 140-character limit of Twitter is a main pillar of its success. Brevity makes writing and reading effortless. Their users love it.
Well, most do. Some want the limit to be raised or dropped altogether. But I believe doing so would kill the very essence of the service.
So what if Twitter offered the option to pay a small fee, say $1/month, to double the limit to 280 characters? If only 10% of their users took the offer, that would be about 30 million users bringing $360 million per year, increasing the company's annual revenues by +260% (estimated at $140 million in 2011).
This would solve Twitter's profitability problem for good. It would preserve the sweet shortness of most of the tweets. Those who want to be more eloquent can now be, because anybody can afford $1/month. And we are all happy ever after?
Surely, I must not be the first one to have come up with this idea. It sounds too obvious.