Design query for job site using subdomains I'm designing a job site in D7. Ideally for better SEO each state or city should be in separate subdomain(this what I've learnt).

For city Paris it'd look like: paris.myjobsite.com 

I'd post jobs using taxonomy categorization e.g. city,state, zip code, field, salary, qualifications.

Now I can host a new Drupal site on each sub domain so for 100 city/states it'd have 100 separate Drupal databases using multi site setup.

The other solution is to have a rewrite rule translating subdomain to site's internal url. 

I'm unable to think beyond this. 

I'd appreciate help as to how this design issue can be met in Drupal.
You are looking for Purl, and would perhaps also benefit from using Spaces.