Say I ping a user in a post. Then I edit that post, without making any changes to the ping (i.e. ). Once I submit my edits, will that user be pinged again? I see people add a space between @ and username on edited posts, but I'm not sure if that's why they're doing that.

no it does not ping again. People may put that space in because they think it might and have never bothered to ask. If you ever do want to ping again, you need to edit, remove the ping, post, then go back into edit and add the ping again.

Personally, I edit pings to add a space for the reason said; if you need to ping them again, you have to edit the post twice, which is kind of a pain in the ass. So like on my CW selling thread, for example, if I have to edit my post already, sometimes I'll add a space to the pings so that next time I can just take them back out without having to edit twice at once.

Cool, thanks guys!