[Newbie] Code for web-based "members" database?

[Damon Lynch]

Hi everyone, 

Does anybody have any suggestions for finding code that will help
solve the following problem:

I have a members database whose main purpose is to allow members to
view other members based on interest areas (and geographical location,
projects etc. etc.).  The database should reflect that areas of
interest are related to one another in non hierarchal ways.  For
instance, supposing an area of interest is biodiversity conservation,
and another area is urban air pollution, and another is organic
agriculture.  Anyone doing a members' search on environment should
find people with those areas of interest.  But someone doing a search
on agriculture should find organic agriculture, and not urban air
pollution.

It would be nice if people could suggest new areas of interest for
validation.

The database is currently stored in a flat file (yuck!).  It could be
stored in a relational database, assuming that is the best way of
storing it.  Or any other manner I suppose!

Unsurprisingly, access to this database is over the web. A relatively
minor point is that I use e-mail addresses from  to send out regular
e-mail updates.

Is there already-existing python code that handles this type of
problem?

Thanks in advance! 
Damon