Be able to mark items not to be displayed in the "best" tab

[icoloma]

The "best" tab is great for getting up to date with HN, but when I have been offline for four days it will also display news from eight days ago, interleaved with the rest. It would be great to be able to mark items as read (swiping or otherwise), or at least define the maximum age of a post to be considered relevant.

An example case: the last post by PG has been there in my top three articles for an entire week. Past the first two days, it's just noise.