Starting needs and long term planning

look over my plan

[Salain]

My plan is to start up a network of sites in the health/biotech fields (where I work). I plan on making a large number of microsites (~20 page on publication, then I'll add more pages based on performance) on specific topics that I will connect together. The main sticking point is whether or not I register seperate domains for each of them or operate them as subdomains under a small set of broader topics. I will be running google adsense as the primary source of income on these so I need to know if anyone's personal experiences with subdomains/linked seperate domains would lead them to favor one over the other. Factors that specifically concern me are 1) search engine placement of subdomains 2) any factors with payouts and adwords 3) Technicogical needs and overhead advantages.

As it is, I'm leaning towards getting a VPS where I control the domain name server and running the sites like widget.healthwidgets.com

I'm relatively new to webmastering, so all advice is welcome and appreciated.

[mack]

It can be a a tricky descision but I would tend to try and get each site on a different IP address (different server/ISP) if you plan to interlink your sites.

Crosslinking can be difficult and sometimes risky.

What I would think about doing is having each domain on it's own host. Then setting up a link circle. In a link circle site A links to B, B links to C, C lnks to D and so on. The last site in the circle then links back to A.

This spreads the linkage across all your sites but prevents cross linking.

Mack.