Creating additional sites link back to main site

Not exactly like the title suggests, but what if I create 3 or 4 full sites with tons of real rich content, do some on and offiste SEO for all of the sites and at a later date put one or two links on each site to my main site.

Each of course would be on their own domain and cover roughly the same topic but be completely different.

1.) Does google check whois info?
2.) Will this help my main site?

 

I think that would be fine.

If they're all hosted on the same ip then the links won't weight as much as if they were from a different hosting but they're still valid backlinks.

 

Yes, apparently they do

Yes, provided that they are on different C Class IP addresses

 

I think it's perfectly natural to link your site to others though high amount of interlinking can affect your sites badly. Even google blogs links to other related blogs, (and so does google homepage), I don't think it's a bad technique unless you go overboard

 

You could get penalised for this. It is domain farming. You would be best to put nofollow tags on any links.