Optimizating two similar website on the same server. Does it matter or it has to be on different server. Basically there both dentist website but diiffent content, does it matter?
If the content is different, then I can use my own scenario as an example: I do SEO work for two carpet cleaners in the same area (15 miles apart), but they are both hosted on the same server. No issues for me as one ranks letter D in the 7-box and the other ranks letter E in the 7-box and #2 in the organics. I like the fact that you mentioned content-differentiation...I think that's the only thing that kept my clients safe.
Before careful not to link sites on the same server/theme/owner as you could be considered a link farm. Just an fyi:
Not at all if you have 2 server then you can point your 2nd site on it otherwise there is no problem.... but make sure both should have unique content and don't do internal linking with them....
If both the sites are trying to rank for the same term and that term happens to be competitive, both sites should be have different class c's. easy tool to check and see if the sites share server. http://www.seochat.com/seo-tools/class-c-checker/ There's a reason why there's tools like this on big SEO sites..
Well if you are looking for ad link revenues then class-c Ip which is different will help, so different server
All this talk of needing to be on different servers / IP addresses is complete rubbish. Read my blog post about hosting multiple sites on 1 IP address and it's affects.
I'd like to see 2 websites on the same server, both on the 1st page of Google for any competitive term.