I did mention this as a comment about half a year ago, but never made a whole thread about it, so here goes:
If you sign up for twitter notifications, and put your email address in the 'twitter username' field, the twitter-bot will automatically tweet your email publicly.
I haven't been affected by this myself, but looking at the twitter bot, quite a few emails are being exposed every week: https://twitter.com/DirtyBoardsPCBs (https://twitter.com/DirtyBoardsPCBs)
I guess the solution would be to truncate everything before the first @ symbol, or just not allow having stuff before the @ symbol, but I'm not a web developer.
So yea just bringing this to your attention. I mean, I know you could say "it's the user's fault", but for the effort to fix it I think it would be worth it.
thanks, I added it to tracker.