Question about free sites/blogs

I have noticed that a lot of the free sites that appear on link-dump sites are pretty much "throw-away" sites...a few pages and 2 or 3 galleries. They get listed and after a few days they fall off the list.

What if I had a free site that I put a bit more into, a more permanent site with lots of content..like a blog. Can a site like that be submitted repeatedly to link-dumps? Is it even worth it to submit a permanent site to them, or are throw-away sites the only way to go with that particular method of traffic generation?

Thanks for all the help I'm getting here...you folks rock!!