Wow. The "Unknown or expired link" is a horrible solution. How bad is it? So bad that even though I've been browsing hacker news for over a year, only just now after reading this did I realize that the "More" link was inaccessible only because of a timeout. It occurs to me that every single time I clicked More in the past, it was after reading comments on the first page for a while, and so it always timed out for me. But the error page made me just assumed it was a bug and that the next page of results would not be possible to retrieve. Was always surprised when I periodically checked the second page and found that this "bug" was never fixed. Why not just show page two of the results, as they are at the time the more link is clicked? Seems pointless to have an expiration for this. So what if the pagination gets a little off-sync and I either miss a post or re-read something? That's much better than getting an error page.