Going through the web, for many reasons, web sites will break navigation (either through one big flash animation, englobing the site in a frame or dynamic loading through AJAX).
Yes engines such as google bot will find it but this is bad for SEO and traffic for several reasons:
- People can not bookmark the content, they can not come back to it as easily even if they liked the content
- People can not share a particular piece of relevant content thus will not bring people to your site. This is especially relevant when you want to develop virality - and be able to do it more than once: if the only thing people can share is the site's main page then after they have shared it once, never any incentive to share it again.
- people tend to come back more to user friendly sites... and allowing to come back to a specific page does go a long way
- It is bad for your SEO - Because your site's content is not as easily shared, you will never get any deeplinking... only homepage links
I understand that in some cases, it might not be an option (example no control over content generation) but still try to have a way to actually navigate straight to the content.