I used to comment on the Huffington Post regularly, but their censorship went out of control. It is a waste of time to write things that will never be seen. Once I wrote and asked the moderators why a particular comment wasn't published. They wrote back that they don't have time to look at it to see.
There always seemed to be certain topics they didn't allow, and that didn't bother me much. You can't write "Sunni Awakening". I could never get any comment that mentioned Dick Cheney causing deaths through. What I thought were pretty insightful comments about the psychology of racism weren't allowed. And I couldn't write about 9/11. It is very common for websites not to allow questions like "How did a furniture fire melt all 84 steel columns of a skyscraper at the same time?" or "How did a commercial airliner disappear in to a hole the size of my garage door?" but the Huffington Post won't even allow jokes about Fema camps. Today they had an article about a reporter getting kicked out of the 9/11 Memorial for asking a question. My comment that there are Fema camps for people who ask questions didn't get posted, and that wasn't the first time. Maybe they even allow the word "Fema" or something. They have automated checks and AOL employee moderators.
As time went on their censorship got more and more ridiculous. Conservatives have complained about their comments not getting published too, but when I can't even reply to an insult, I suspect the moderation has a conservative bias. But for the most part there just doesn't seem to be any rhyme or reason to the censorship. I think the moderators just think it easier to censor something than to give it any thought.