Stack Exchange is the only site on which I use the username pacoverflow. Anyone with the username pacoverflow on a different site is not me.
Stack Exchange wants you to ask and answer your own questions:
"It is not merely OK to ask and answer your own question, it is explicitly encouraged." -Jeff Atwood, Co-founder
They also want you to make up questions you think will be useful for others:
"I'd love to believe thousands of people decide every day to make up questions they hope will be interesting to others" -Shog9, Community Coordinator