not really bookmarking as the author will put the tags but more of a way to retrieve/consume content by category.

so it almost sounds like it's more of a bookmarking use-case for you than a collaborative consumption surface?

would a simple bookmarking feature help or would you need to separately curate your bookmarks with tags?

I image it more like on twitter to start simple. In a second step having it as a collaborative mechanism. 

Regarding the current volume, it seems already interesting to organize the post to be able to retrieve them later. For me, right now, SN is good for the immediate consumption but not easy to look for past posts. My 2 cts.

fredl

SN improvement idea: tags

are you imagining only the original author could add these tags like on Twitter or would they be community contributed like on Quora?

do you believe there would be enough volume today in any given tag to make consumption via tags an important interface for users?