You must never use your Real Email Address to join a site (save Paypal). Don’t use it in Facebook or Twitter or anywhere, save to send and receive personal or business emails.
If you use your real account to join a site, be prepared for trailerloads of email from all sorts of places and people.
For example, I have an account I use to join sites and every day there are 50 or more pieces of garbage in it from places I don’t know.
On Facebook I mentioned that I would love to take a cruise. Suddenly the email account I used was jammed with all sorts of ads for cruises.
I took a survey once and since then, the email account I used is overflowing with political invitations.
All it takes is one mistake to turn your email account into a rubbish dump.