[thelist] Scripts requirements

Hi all

I'm helping to develop what might turn into a very large site and we've got
a couple of requirements and I was hoping that someone on here might be able
to help fulfill them.

What we want to be able to do is to allow users to upload their documents to
the website.  Other users will then be able to do a key word search to find
documents of interest to them.  They should then be able to read them.

What I imagine happening is that a script will run when the document is
uploaded to produce a list of keywords.  This would then go into a database
which the users looking for documents would then search through to find
relevant documents.  Ideally they would be given the title of the document
along with it's relevance.

What we would also like to do is to alllow users to register keywords which
they are interested in and to be emailed notification of new documents which
match those required keywords when they are uploaded.

I suspect that we're going to have to pay lots of money for this but I was
wondering if anyone could give an indication of how much and where we could
find such scripts.

The site is going to be hosted on an NT machine so either ASP or Perl
solutions would be happily accepted.

Thanks in advance