Why do colleges spam so much?

[thegathering]

The past two times I took the PSAT and the last time I took the SAT, I chose to select the "inform me about other colleges" box with my email on my information form. Ever since that day, for the past two years, I have been sent between 5-30 emails a day from various private colleges, many sending at least one email every few days.

My question is, why do they keep spamming my mailbox? Do they not realize that if I do not respond to their automated mail server the first three times, I probably won't respond for the next 20 times?

Why do they not just give up and put their resources to better use? VMI, at least, gives up after 6 months of spam. These other random colleges just don't stop.

I really wish these colleges would sent a singular email message to me about their college and leave it at that. I don't use that email account often, but every time I do I have 300+ college spam messages .

Anyone else have this problem? Anyone know of a way to keep these colleges from sending me mail? I made the mistake of selecting that little box, now is there a way to unselect it?