It's been pointed out to me that this has been submitted before:
* http://news.ycombinator.com/item?id=3251877
* http://news.ycombinator.com/item?id=3703024
In fact, the question has been discussed several times:
* http://www.hnsearch.com/search#request/all&q=title%3A%28...
My personal observation is not quite the same as DanI-S who says:
it is apparent that timing, rather than
the quality of the link, decides whether
or not something reaches the front page.
My observation is that it is a combination of timing, title, content, and luck. Timing does play a huge part in it, but if an item has significant merit, it usually (or at least often) does well despite poor timing.
It's complicated, and unless you pay attention, good items will pass you by. That's why I'm working on a site to augment HN and try to capture good items.