Spammers verifying email address?

A couple of weeks ago I got an email from a company that wanted to advertise on my site. Actually the sent me a separate email for each of my poker sites.

I replied to each one of them that advertising information is posted right on the site. I offer both text links and banner links.

I never heard from them again. Until today. I just got the same type of emails, but sent to my websites in a different niche than poker.

Now, since no reply to the first, I think it's spammers just verifying email addresses.

Anyone else seen these or have any ideas?

Yeah, these are all over the place in our industry currently. Just go to CAP (CasinoAffiliatePrograms) forums and read the threats.