To alleviate your concerns, please know that Aeria Games is not a spam type company and they are wholey legit ^_^ in fact one of the better gaming portals on the net in terms of F2P premium based games.
How your email made it into the database is a bit of a mystery, though there have not been any official statements, and so this is just a guesture, but its possible your email was ported in via a partner.
Aeria currently partners with Perfect World, EA Origin, Sony, Facebook, and several other smaller partnerships from Browser games, and even including Google which now owns Meebo.
I do not know if aeria participates in advertisement selling of email addresses, but to the best of my knowledge they don't.
In either case, I wouldn't be worried.
If you do not wish for the account to be associated to your email, you can opt out of any and all solicitations or newsletters in the Privacy options in your accounts profile, or you can write a ticket via Contact Us (located at the bottom of the page) and request your account be terminated.
^_^ anywho welcome to Aeria, hope you change your mind and would like to check us out for awhile