The good news is that the web is a dynamic, ever changing place. Expect change - it is a constant in the Information Age. Once you have identified your key words the first time, its no big deal to search your favorite topics every month or two. You will find new sites popping up all over the place. Also, go through the index sections of your personal Super Site collection and look for new stuff.
Most webmasters place a gif next to the cool new links they have found.
Read the Monitoring the Internet section of NeoLink weekly and browse through the exceptional listings of new stuff out there. There are new, cool sites listed every month and the latest developments on the Internet. See especially the link to the Berkeley Public Library . Its a big place out there, just like the rest of our lives. You will never know all there is to know and that has never been more evident.