To be fair, they've been testing since 2010 I think. I haven't gone over the 250 GB cap in a while, but I don't download everything I buy immediately, and I don't stream any HD media (but I should).
This particular testing was announced around May, I think, and they were supposedly going to start the actual testing in the summer of 2012. One of the new plans is a 300gb cap (instead of the previous 250gb cap), and you pay $10 for every 50gb after exceeding it. I don't think any plans were confirmed yet though, so I'm not sure if they'll go through with any of it.
I go over 250gb pretty often, so it's an issue for me.. but they've never done anything about it in the past, so I guess I've been lucky.
Edited by spoderman, 26 January 2013 - 03:27 AM.