It could be just you, then again it could be just me, or it could be both or all of us.
I noticed this after joining a email list for a gaming company I wrote something for. I sent in the blank email, the reply said, "one click registration". I have no idea if it was needed for me to click that link or not, but it wasn't 1 click registration, instead I had to fill out a "3" page form, but I only got to page 2 before saying screw you. The reason? It would not let me go to page 3 without checking one of the dozen boxes indicating I "wanted" spam from one of those topics.
The thing is, when I checked my email I found spam from this company saying, "Congrats, you are registered". Then another 3 regarding my attempted login/registration.
The next morning I woke up to 23? spam messages, up about 90 percent from normal I'd guess.
So, my advice, do not sign up for topica.com .