SSD's are kind of like re-writable CD's DVD's etc. You are limited in the amount of times you can write to it, and each time you do, it degrades ever so slightly. That's why defragging is bad as well as an unconditional format. A quick format just makes the data so it is not seen and can be overwritten but it's still there IIRC.
That's why it's important to buy the extended replacement warranty on them that Newegg and others offer because eventually they are going to die. Those old huge 60MB HDD's with the big metal tops from the 286 days laying in the bottom of our closets will still fire up long after we've gone through our 5th or 6th SSD. :)
That said, I can't wait to get a couple when the price per Gig comes down a bit on them. :)