100,000 users clicking reload every second. 500 posts per second. And there's a text capacity on an article text body.

buro9 : This is just a complete conjecture. I do not know Reddit's internal hardware infrastructure. I just know that real-time police radio transcription is the best news source, bar none. And it's getting hammered.

Certain threads generate enormous amounts of activity, and the reddit infrastructure will automatically place those threads into a temporary 'Read Only Mode'. This effectively ends the thread when it revolves around rapid updates, so redditors normally start 'Incident Thread 2', then 3, and so on.

During the Boston Marathon bombing, there were, if I remember correctly, over a dozen threads that continued the original conversation, simply because each of the previous threads kept getting hammered by people posting comments.