I am building a micro-blogging page where everyone can post about everything and it's shown on some kind of a post-it-wall.
Older posts disappear fast (depending how much is posted, of course). Users can't access a single post with links on the page itself, but I've implemented an algorithm to have a single post on top of all the other posts with a direct link which I will include in a dynamically generated xml-sitemap.
The links look like this:
Now I fear that my pages will get a duplicate content warning, as the only difference between those 2 pages will be the first post, the following posts would be the same (given the exact same time of a request).
I know about the canonical tag, but that's dealing with the whole page. Is there any way I can show SEs, that only a part of my page is relevant?
Thank you for your ideas!