Strange forums indexing (not session-var-related)

google indexes the forum page shighly after initial crawl but then drops

[piramida]

Very strange behaviour from google - I'm running a website somedomain.com PR5-6, recenty wanted to add a forum for that domain-related discussions at someforum.com - since I had the domain name basically unused. Two names are not related (someforum and somedomain) but are interlinked where appropriate.

So, few days after someforum.com is launched, google spiders all of it's pages and ranks it amazingly good (for a pr0 site) - making it top1 for a pretty competitive search. Surely, afraid to break the magic I tried not to modify templates much, maybe changing a couple of words to make it even more attractive.

After recrawl a week later... all of the pages were dropped. Another few days passed and a couple of them got back but nowhere near the top-100 for that same search terms.

So that got me thinking - I was surely not doing anything illegal, there was no duplicate content, apart from the thing that forum.somedomain.com was a 302 redirect to www.someforum.com. Could that be a reason for the drop? Or the fact that both sites are running on the same ip address and are interlinked? The penalty did not affect the main somedomain.com site, only the forums subsite.

Or is it a standard behaviour for forum spidering? G detected that it's a forum and penalized it?

[ciml]

My guess is that you're seeing the normal fluctuations as Google try to feed new content through their various datacentres. If so, you may appear then disappear again for a while. After a while you'll hopefully find it more stable.

[piramida]

Surprising but results were consistent across datacenters (at least two that I usually check).

I'll monitor the progress, also do you think it makes sense moving the forums site to another ip? (paranoid that G may consider the two sites an cross-linking network of some sort).

[seofreak]

no, not necessary.

[dirkz]

Maybe you got some boost for freshness. What was the timetable, when did google crawl it, when were you dropped?

I wouldn't switch IPs, if you linked the two domains properly (and legit).

[piramida]

Quite short; around 4-5 days it was on the top spot and then one day all pages but one has been gone (and I've spotted a googlebot visit in logs a day before that).

Maybe it has detected that the forum is not very active yet and removed some special "forums should rank higher" magical rank multiplier? :) This sharp turn of behaviour from 'spider all and make it high rank' to in a few days 'drop them all but one and rank it in the geocities neighbourhood' is surprising to me, I'm used to googles stability over the past 4 years I've been monitoring my sites ranking there. Maybe it just visited at the time the site was down for a minute? this happens though I've never seen substantial amount of pages dropping from google with the main site even after hosting change, when site experienced *weekly* downtimes.

[piramida]

ok, was a temporary glitch; changed the ip of the forum site (not sure if it actually was needed), few days later when google respidered it's all back; a little lower (pos #4 now) but all pages are indexed allright. Second and third crawls it was picking up only one page from the whole site though.

Hope it stays put now :)