When entering my email into any field online I'm always worried it's going to be used by more than that site. It's just unavoidable now a days not to have your email receive massive amounts of spam, even if you're careful. But, there is an easy of tracking and even filtering this out!
The trick lies in how Google handles email addresses. Lets say your email address is
email@example.com . You enter this into forms online when you register for new services, which you do often. Instead of entering this email in there, try entering
firstname.lastname@example.org as the email address, where thissite.com is the site you're signing up for. When you're viewing your gmail account, this email will look exactly like anything else in your account, but the text in the "to" field will be
This opens up a goldmine of information, because now you'll always be able to filter for not just emails from this website, but if they ever sell off your email you'll know who did it. If things get too bad, you can just create a filter that maps any emails to this account straight to your trash can where they deserve to be.
Just for the record, some places actually validate your email address for this, but most don't seem to. I know there are more than a few gmail hacks on www.lifehacker.com , probably some other helpful tips there if you're looking to optimize your email browsing.