"If the DNS server points to 2 or more of your websites which are hosted on the same IP address, it is called reverse IP cloaking. It is a black hat technique. Why would anyone host a multiple number of websites on the same IP address?
Because, to gain more back links for all those websites. As, most of the web pages of those the websites in this case are interlinked to each other to get more number of incoming links. So, this is considered to be a negative factor in terms of SEO."
The rest of the article is sound - this part is just convoluted and wrong. You can have multiple websites on the same ip and not have them linked to one another. You can also have multiple websites on the same ip and have them extensively linked to one another and suffer no penalty. You can also have ten of thousands of websites on ten thousand different servers and have them all interlinked - what's the difference?!
And as HomerJ mentioned - millions of websites fall into this category of being on the same ip - it's called shared hosting and/or with add-on/extra domains! Every search engine knows this - but clearly the writer seems to misunderstand the obvious.
