Hi! Let's say I have a website about travel and now I want to create a separate websites for each of my destinations - like travel-spain.com, travel-france.com etc. Each of this pages would have a unique content. I would than link this pages to my main travel page. Would it make a big difference if I host all pages on the same server or if I put every domain on different server???? Thanks for you help
The IP address as well as the server's location, domain owner and any other info that could indicate to a search engine (Google) that these websites might be part of some linking scheme, might give you lower value on the linking. To avoid that, you can assign different C class IP addresses to your websites. Even better if you can have each website in a distinct physical location... but sometimes that could turn to be too expensive. On the other hand, if the quality of the content is high, the content is unique, and you also get some nice links from out of your server, don't worry about hosting these sites on different servers. It will work just fine having all of them on the same machine.
I'd just put everthing on the same server. If they are all related, you can link them together logically without being spammy. One option would be the hub-and-spoke method where all the destination sites link to your main site, and the main site links to all the others. Plus, there was a Q&A with someone from Google (not sure if this one was Matt Cutts or not) saying that domains are treated as separate sites, even if they're on the same IP. And anyway, Google could also tell they are all your sites based on the whois records.