Keep in mind that purchasing a list from a list broker will likely mean they have sold that same list to hundreds of other investors, possibly thousands and those poor people on that list likely get junk mail and spam calls all the time.

A lot of bigger wholesalers or less experienced just spam out a huge list of everything they have and a flipper may ignore their list if they have to look through too many deals.

Big bank will break even on the mortgage to earn your loyalty, cross selling is now a factor. 20% down on a $1m home given the 'normal' sales prices in the area, no one's going to touch the big banks, just be ready to be spammed by for 10 million other financial services you might not need or want.

Are industry professionals seeking customers doing so by paying to be here, or is it spamming? 

These scumbags constantly bombard my email inbox with spam that is focused on that -- screw over someone's grandma, and you get a big paycheck!

I'm generating my own prospects from the web, they are not registered on my website.Is it something that can be considered as SPAM? 

Let's talk about keyword spamming instead.  

GTFOH with your spam.

If that's all the information you've been given I'd put this sender on my spam list.

Than I saw the amount of "Spam" I received.