I'm working with a mailing list archive and am tasked with setting up basic search, boolean search, and ultimately some sort of more intelligent tag-based searching.
I see both commercial products and some open-source projects (like Lucene.NET)
Has anyone else done any similar kind of work?
I'm working in Win2k3 server now, so the immediate thought was to use ASP Classic or ASP.NET. However, if there were another platform that was orders of magnitude better for the purpose, then I'd consider that as well. I'm not going to throw out something becuse of that ;)
Since you are setting up mail search you will need two things : a search engine and a database. There are many search engines that offer what you need.
They provide advanced search tools like keywords, field-restricted search, boolean queries, phrase search and more. Here is another SO post looking into various text search engines: Comparison of full text search engine - Lucene, Sphinx, Postgresql, MySQL?
Sphinx and Solr are pretty fast in search. Sphinx does full database search and also does partial indexing. Solr uses indexed based search, and is scalable with almost linear performance.
Second most important choice is the database where you store your mails. The mails will be in some format (schema), like fields in a table. It would be plain crazy not to use any format. It is not file search, right? Some search engines require particular DB's to work. Sphinx uses SQL databases only, Solr can be integrated with noSQL databases.
If you are not worried about scaling issues (you have thousands of users, having GB's of data, needing real time performance) then, you are fine with SQL databases. Otherwise you will have to use noSQL database with Solr.
SQL databases(like PostgreSQL) are simplest to work with, do what you need and require minimal setup/effort. Connectors will allow you to send query(mail search) from browser to your database.
Also you said you use Win2k3, you will have to switch to linux distribution to take advantage of these search engines. Win2k3 is slow, does not offer performance comparable to linux distros.