I'm finding specialized search and vortals a facinating topic lately. Mostly trying to work on gathering worthwhile links from those type of sites. I'm doing ok so far but would appreciate any good tips on pulling up viable sites per topic area.
I'm also interested in finding out more about edu sites and their link popularity ranking.
The best place to find vortals, specialised searches and trade directories are major directories. In the past, I have tried many ways to track thoses. The idea was to built my own database of these resources. I began the hard way using Copernic. I believed then it was the best since it checks primary results to filter out dead links (7 to 10 %). It can also export results in dbf format. I ended up with a little less than 20% of results were relevant. There is a lot of spam and scam out there. What I found on directories was 3 times better ratio.
The biggest effort is to surf all that and to store all relevant datas in the right fields so you can later retrieve and sort them faster for later use. Company name, url, submission form url, type, country, categories, entry or annual fees, technology used ( static or dynamic) languages, ect.
It is really worth the effort of sumitting to vortals and B2B directories. Had very good results with it.
Zeus is a good tool for finding sites with related themes, although it doesn't necessarily find "good" ones in terms of page rank, etc. in preference to others.
One suggestion that appeared here a while back was to search for "links", "link page", etc. along with your keywords - the sites you find this way are probably far more likely to add your link than others. (The same caveat as above applies - these may not be the most "important" sites, but you stand a good shot at getting a link.)