I don’t know why I didn’t think of it before, but students both asking and answering questions at the various online Wiki-like sites like Yahoo Answers, WikiAnswers, and Wikianswers (yes, the last two are indeed different sites) are definitely examples of writing for an “authentic audience.”

I’ve added them to The Best Places Where Students Can Write For An “Authentic Audience”.

I had considered including students writing in Simple English Wikipedia, but decided that it was just too complicated for English Language Learners (and even me!).  These question/answer sites, though, are pretty simple.