On my forum I am doing I have modrewrite, so a topic I have called 'celebrity pictures' the url is - http://www.mysite.com/forums/t501-celebrity-pictures.html (Hover over the url to see it all) But when it shows up on the main forum index as 'last post' if a post in that topic was a last post it shows up as 'p1469-celebrity-pictures.html#p1469'. So if a search bot goes to the topic via the second url as it's on the main index page then goes back to it at a later date when its been posted in again but this time via the first proper url,will they might think it is duplicate content?
The search engines will just show the most relevant page in the search results and ignore the other one.
You won't get a penalty. Although you might want to 301 redirect 1 page to the other or change the link somehow.
It's on a forum so I cant redirect, one is just when it shows up as 'last post' and one is the actual url.
You should be able to alter the link or add a redirect in your htaccess file. Maybe ask the people who you got the forum software from if they can release a patch or update?
They just say its not a problem, they said 'Trust me, there is no problem with this, because all the redirection is done within Apache mod_rewrite and is transparent to the Googlebot. For example, youc an access our forum via community.xennobb.com or www.xennobb.com/community. No penalty for duplicate content, redirection is managed by the mod-rewrite engine so Google understands the situation. Don't make the mistake to consider G as dumb' But I am not so sure?
Not sure I understand the question? The forum in question comes with SE friendly urls auto, so if a topic title is 'blabla.html' thats whats the url is in the address bar, 'blabla.html' not 'showthread.php' etc. But on the main page where there is 'last post' the url is different, the post number is in the url and so is different, as explained in the first post thats why I wondered how Google would treat it - I am worried about being penalized for it.
Maybe this can help your forum issue - with or without mod_rewrite. I was reading the info in a related phpBB mod - [Beta] SEO Urls V2 ("avoid_double_content.txt", part of "mod-seo_urls_v2.zip") which can be found here. They do this by using anchors in the links for the specific post. Hope that helps - if you don't have a phpBB board, I am pretty sure that similar code can be written in your topic pages that create two links for the same page.