DataTrak allows you to select which engines to send your queries to, and then you can switch between the separate returns from each engine. There are many collections of metasearch engines. Freeality and Karl Heinz Resch's page have a wide range which can be queried directly from the web page. It is important to remember that the query is at least as important as the database. These sites are good for quick specific search queries, and they are adding more complex queries all the time.
Detailed enquiries ought to be done on the main engines using their advanced query techniques.
Searching Newsgroups DejaNews is the major search engine for newsgroup queries. The database gives access to topical information on a huge range of subjects submitted from many countries. Items can also be posted to the newsgroups. Some of the metasearch engines can also search this archive. You can now use it to monitor and send emails to newsgroups.