If you’re reading this on the site (as opposed to the feed) you’ll be seeing a rather brash and obtrusive advert, probably just above these words. And if you’re reading from the feed and come to leave a comment or whatnot you’ll also see the advert.
And then, the next time you load a page on this site, you won’t and never will again. Assuming you’ve got cookies enabled, but who these days doesn’t?
In short, it shows you an advert and places a cookie in your browser. The next time you visit it looks for said cookie and if it’s there then you don’t get no ads not never ever again.
So enjoy the ad while it lasts.