Hoople - 4:48 pm on Oct 25, 2012 (gmt 0)
google will not rank similar content or domains on the same IP for the same SERP
Interesting, do you have any hard evidence of that?
In my one micro niche I have 4 sites all on the same IP. These sites' niche is 3 tiers down from the primary niche's (the vertical) top. All rank well in Google and in Bing for their primary keywords. Three are EMD's for their primary keywords.
All are not for profit, nothing commercial at all on site, no text links, no link networks and no ads at all. Most have >500 words on the homepage with less than 5 images. All but one are single page single purpose sites. All have a Wordpress blog as well. How small is micro? All get less than 10,000 visitors a year. All are interlinked to each other and have many outbound links. All are in Google Webmaster Tools/Google Analytics too. Been ranking like this and improving (me building inbound links) since 2009.