The Answer is “create a new email address for each site you opt into”. Sounds very complicated right?
Well if you have your own top level domain xyz.com, you can easily catch all the emails sent to your domain and use a separate email for all such opt-ins.
What if you do not want to be using your domain emails for all such free offers? Now it sounds a bit complicated but actually it is not that complicated. Most email provider will let you use the + symbol as a separator and you can append whatever after that to track that email.
For instance let’s say your email is firstname.lastname@example.org and you wanted to subscribe to IMTips’ Free Course.
You can use email@example.com to subscribe.
GMail, and most other email providers supports this and will ignore the + symbol and anything that comes after it and you still get the email. Try it out. I have tested for GMail myself.
You can use this trick to know if people are selling your email address and if you sense that they are, simply filter it out based on the email address.
Further Reading …