Have you committed any blunders on the internet - big or small? Something you wish you could retract or just something that now seems funny, silly, crazy or otherwise, but was not intended to be so at the time. If you've been active on the big net for some time and claim that you've never made a single blunder, you're probably a liar
So let's have them. I'll start off with something that popped into my mind (I may recall other things later) : When I sent my first email ages ago, I didn't know that my own address was automatically visible to the recipient and that he could just click the reply button. So I ended the message by telling him my email address so that he'd know where to send the reply.