Why is it that if you Report Spam from your Mail list on the main site it gets deleted automatically, but when you Report Spam in game you have to delete it manually?

Shouldn't the in game button be able to do the same thing as the website button does? Report and Delete in one click and one confirmation.

Agreed. I would love to see the in-game functionality match the website functionality where spam is concerned. A filter would be even better (e.g. auto-flag any message with "www.ign" in the body or subject) like a mail client.

My kids tell me that some one tried to sell them energy credits while in game. Is there a fast and easy meathod of reporting this?

Right click on their name and click report.

It may not take the 1st time, though. So you will have to keep doing it until you see a message saying that that person was also added to your ignore list come across your center screen.