There is a site\resource that offers some general statistic information as well as an interface to search facilities. This search operations are costly, so I want to restrict frequent and continuous (i.e. automatic) search requests (from people, not from search engines).
I believe there are many existing techniques and frameworks that perform some intelligence grabbing protection, so I don't have to reinvent a wheel. I'm using Python and Apache through mod_wsgi.
I am aware of mod_evasive (will try to use it), but I'm also interested in any other techniques.