[thomassmith65]

The apparent 'ban' may related to the site's popularity.

Who knows how the algorithm here works exactly, but people submit daringfireball links regularly...

...and few HN users would like HN to function as a link aggregator that just shows a random selection of the same dozen sites, day after day.

One solution would be to penalise domains a little the more frequently they are submitted. Seems like a plausible explanation.

[jachee]

The frequency with which Wikipedia links hit the front page sorta bucks this idea.

[thomassmith65]

That may be right. Unfortunately, while I have seen Wikipedia articles on HN, my memory is not sharp enough to recall for how long they stuck around on the front page.