Ryan Smith's first words after cycling accident without helmet

I wonder what this has to do with car maintenance. Or is going off topic OK for Cheerful but not others, such as on U.R.Cycling where Cheerful regularly refutes responses to his trolling by claiming them to be O.T.

Just a case of accidental wrong newsgroup, I cancelled it within moments, but apparently the cancellation is not universal, obviously if it had been deliberately posted here then I should/would have marked it OT

Once a message is out there, it's out there, and you can't cancel it from the thousands of servers that now have it.

You're only half right. In the early days of Usenet it was entirely possible to cancel messages. The cancel was distributed in the same way as the article itself and servers receiving the cancellation deleted the article. Unfortunately, there was very little authentication on these cancel messages, so they were trivial to forge. As a result of the subsequent abuse, hardly any servers honour them any more. There is a strongly authenticated system in place to allow spam cancellations to take place, but days of users being able to cancel their own postings are over.

That sounds as though I'm completely right.