[SpamCop-List] What's the point?

[Bill Beyer]

OK, so I've been getting a ton of slimy porn spam on a yahoo address. Like
on the order of 50-60 a day for quite awhile. The vast majority are
spamvertising sites hosted on IPs controlled by yahoo, prob just redirector
sites.

Just recently however I've notice that the URL format for some of the
spamvertised sites has changed. Many of the sites now look like this:
http://www.sonicaurora.info/maturewishes.html?n_nbyylr.ljcvv,hvx . It
doesn't take a genius to figure out that n_nbyylr.ljcvv,hvx is a coded
version of my email address, x_xxxxxx at yahoo.com .  l = y, j = a, c = h v =
o, etc. The "." is used for @ and "," is used for "."

The question is what's the point? Why would the spammers care? Do they
intend to listwash me or is it simply so they can verify that this is a live
address? Why would you want to add an anti-spammer to a mailing list? I
counted 21 of these in the last 2 days.