This year I've given each student their own personalised iPad and set of already cut up posts (which are also personalised). At the end of the day during reflection time, each student will post a 'tweet' on their iPad. The students love it!
It took a bit of time at the beginning of the year to set up (photos, formatting, printing, laminating, cutting etc.). But now that it's all been done, it's extremely simple and easy.