Are you worried about spam in your precious gmail account ?
If yes, then you would like to consider making aliases of your gmail id to use when you're not sure whether you're signing up for something safe or not.
It is a very simple task to provide an alias of your gmail id. Whenever you sign up on the internet on some site that you think may not be safe (or a site which might send you spam),all you have to do is give out the email address as
For example if your email id is james@gmail.com,you can provide james+21@gmail.com or james+test@gmail.com .You can put anything after the + and all email sent will still go to your gmail account.
In the event that you did give your email to a spammer and you start receiving spam, don't worry! Just create a filter, and make everything that is sent to username+whateveryouputhere@gmail.com go to the trash. This way all the spam that you might get will automatically be deleted.