How does Google (and search engines in general) handle the indexing of forum pages?

A busy forum can have tons and tons of pages.
Typically, I would think Google would regard 10,000 pages all with a link back to the main site as potential spam, which could hurt the site's ranking. But I'm sure Google has figured out the possibility of running across busy forums with their indexing bot.

Question 2 - Would Google actually spider every single page of a forum? Besides being a waste of bandwidth, this would seem like quite a task for just one site. If it stops at a certain page count, could this possibly leave out the indexing of non-forum pages?

Question 3 - Have you ever seen a forum page get a high ranking? I haven't. Forum topics can be long and filled with keywords, but they never seem to make it up top. Not that I want forum pages to get a high ranking, but it makes me wonder if the indexing of forum pages will pull down the rankings of non-forum pages on the site (due to sheer abundance).

whatever you do, make sure googlebot does not index your forum images :mad:

now THAT is a bandwidth whore

Google may index deep enough if your site has a high page ranking.

Google will not, however, index many dynamic pages (eg PHP, ASP etc) for fear of overloading your server.

I have found many forum pages within google, but not probably as many as exist (translated - I am sure it doesn't index all sites forums fully...)

Originally posted by kreativ
I would think Google would regard 10,000 pages all with a link back to the main site as potential spamGenerally, no. What's considered to be spam in linking would be a bunch of pages from different domains linking back to a main site. Since each page of a forum would be on one domain (even though possibly not the same domain as that "main site") it wouldn't normally trigger a spam filter.Question 2 - Would Google actually spider every single page of a forum? Besides being a waste of bandwidth, this would seem like quite a task for just one site.As jasoncart suggested, the number of pages that might get indexed from a given site seems to be related to the PageRank of those pages. There certainly are sites with thousands of pages indexed at Google.If it stops at a certain page count, could this possibly leave out the indexing of non-forum pages?It could. It's not a bad idea to make sure, through the design of your linking structure, that your most important pages have the best PageRank. Usually, though, having lower PR for forum pages will just naturally happen -- generally there's only one link, or a few at most, to each forum page and generally several more than than to content pages.Question 3 - Have you ever seen a forum page get a high ranking? I haven't. Forum topics can be long and filled with keywords, but they never seem to make it up top.Page titles that are "long and filled with keywords" are in no way going to guarantee good positioning. And, in general keyword presence in forum pages is not very good. But yes, I do find well-ranked forum pages very often. Webmasterworld is a good example of a site for which that happens -- and it happens in large part because of intentional design decisions, as well as because the site's pages all carry a pretty solid PageRank.