What are aggregators?

First, this site is not one.
Some of the links to the right under “Gadgets and aggregators” are.
They use technology and tags to automatically gather links to blogs or other aggregators, and then repost the content. No editing. No human thought on whether the stuff is good to read. Handy, at times. But you can spend tons of time wading through stuff to find the pony underneath.
Here’s hoping that the links here give you a clearer path to the pony.