Something new I have learned today about how awesome gmail is.
The e-mail address itself can be dynamic, for example, for an address of whoever@gmail.com, you can make it into whoever+whatever@gmail.com, and it will still be delivered to whoever@gmail.com. With this new concept, it become even easier to filter emails. For ebay account, I can have a whoever+ebay@gmail.com, and then add a filter to filter all the emails that are sent to the ebay address.
I have also discovered that you cannot send emails to other gmail account with the “+” technique, but you can send it from other accounts as Yahoo!.
neat