Sometimes the Validation email does not automatically send, to send it manually please go to Options -> Account info. From there, check whether the email address you entered during sign up is valid, and then press "Send validation email"
Then please wait a few mins for the email to arrive in your inbox.
1. Sometimes the email is misidentified as spam and may be placed in your junk mail folder, please ensure you have checked this
2. Using aol addresses has known issues, if you have signed up with an aol email address, please use another address (Many free email providers can be found using a search, I recommend Yahoo)
If you still have problems, post your e-mail in a thread in Ask -> Email Validation.