Cable filters and if anyone has used one before?

Just finished reading some threads/posts so I decided to go ahead and post my experience. Just a little over 8 months ago now, literally the day before my second daughter was delivered, my oldest boy came into my office/dining room (no jokes please) with a grin like the Grinch on his face. He wanted me to buy one of those digital filters. He always has me paying $50 for his wrestling WWF stuff and I’ve also been known to watch a good boxing match every once in a while. Long story short, I got one of those cable filters for my ******** DVR box in the living room WITHOUT, telling the kids or the old lady ;). I still make the kids ask to order stuff but when the bill comes there’s no sign of anything, heh. Every month I squeeze about 30 PPV’s out of it without having to clear the memory on the box. If I only order like 20-25 ppvs in a month, then I don’t need to clear the box because it clears on its own every 30 days. I figured if it didn’t work I’d just get my money back since they have like a year guarantee or somethin like that (had to check my bookmarks www.cableboxfilters.com).
BTW, does anyone know what the Cablecard slot does?. I’ve never seen anyone who used theirs and I don’t understand what it would be used for. Is it for the cable guy when it’s being installed or something?
Thanks and God bless!
L. MacArthur