Forum Moderators: Robert Charlton & goodroi
Could that have been the reason my PR was killed? Thanks for your help, I'm a little concerned.
Also, forums would usually be just one subdomain of a principle domain name -- if they are even on a subdomain at all. The thing about subdomains is that they are treated as distinct sites, definitely related in a Hilltop way, but still distinct. They don't cluster or indent on the SERP for instance, and can appear as a separate result on the same search. So such cross-linking might threaten the integrity of the search results when, as sven1977 says "All subdomains are related in topic very closely."
> Why use a subdomain book.example.com and split up the PR. One would just use example.com/book and get the benefit of an organized structure and keep the PR on just one domain.
PageRank is per-page relative thing, not per-domain. If Google didn't change original PR distribution algorithm - there should not be any difference between book.example.com/ and example.com/book/ if they have same ingoing and outgoing linkage.
Otherwise, if Google rewrote rules (if it penalizing subdomains from similar IPs, etc.) - I'm washing my hands. But I don't think so - I see enough examples of havy 3-rd level subdomains usage without any visible penalties.
I guess the trick is not to crosslink between niches, i.e. building subdomains for:
cars.example.com
shoes.example.com
jeans.example.com
if you have started your website as one that sells examples only.
Keep your greed tight, use subdomains for your users or at least your own experience and they will work just fine.
As far as I am aware we have never had a penalty applied due to the heavy interlinking but all sites where launched with the interlinking in place.
My understanding is that you wouldnt be penalized for interlinking relevant sites as most major networks do, I thought G would just discount any weight given by those links though. These are not subdomains though so maybe that doesnt apply in this case.