Someone else had a near-identical experience to the one I described with CommonDreams, which they wrote up last night in a comment on the same "Overcoming Censorship" article on CommonDreams here (comment 11). That's my saved version, because--as I'm sure you couldn't possibly have guessed--by this morning CommonDreams had removed the comment.
I'd been holding back a bit in my first posting on this issue on the theory that there might be some other explanation--like, say, someone tripping as they walked by a laptop that had an active MySQL session going, banging into the keyboard, and accidentally typing out "DELETE FROM WP_COMMENT_TABLE WHERE WP_COMMENT_USER = 'distantocean' OR CONTAINS(WP_COMMENT_TEXT, 'distantocean');" with their elbow and then inadvertently hitting the ENTER key with their nose as they completed their fall, no doubt theatrically screaming "Noooooooooooooo!" in the milliseconds before they made contact with the floor. Hey, it's possible.
But at this point I feel confident in saying, with no hyperbole, that the CommonDreams editors responsible for this are worse than the Stasi and the Gestapo combined, and that if they had their way we'd be living under the yoke of their tyranny day after grinding day, lashed mercilessly for even thinking forbidden thoughts of the bright summertime we'd lost forever to their iron rule.
HIGHLY AMUSING UPDATE: I submitted my original posting to Sunil K. Sharma, the editor of Dissident Voice, who in my experience is an all-around cool and friendly guy. He responded as follows, and told me to feel free to publish it if I wanted to. I think you'll see why I've decided to take him up on that offer:
Common Dreams is run by a bunch of assholes. Dissident Voice articles are banned from Common Dreams because we took them to task for posting a couple of articles of ours without permission or without citing us as the original source (we only ask that people do the latter, they don't have to ask for permission, though it's a nice courtesy) a few years ago. They ignored my repeated calls and e-mails to rectify the matter and so finally I sent an e-mail threatening a lawsuit for infringement (I wasn't serious, just trying to see if they'd actually respond to that letter). Chris Brown, or whatever the slimy fucker's name is who founded Common Dreams, then responded by calling me a lunatic and proceeded to remove the articles in question without any explanation to CD's readers, and said he would inform his staff that any submissions from Dissident Voice were to be banned. We tried to make nice a year later and CD ignored us. They have to cite original sources for the articles they post when it comes from mainstream publications, but somehow they feel they're not obligated to do the same with alternative sites like DV.
LESS AMUSING UPDATE: Yet more accounts of CommonDreams' overweening control freakery are available here and here. So my experience is by no means unique; they've apparently been at it for as long as they've had comments.
BRAIN-SEARING IRONY UPDATE: As if there's not already enough irony in CommonDreams' practice of censoring political speech, their (apparent) webmaster has a blog, and he has a posting there titled "We've always been at war with Eastasia." He also has a sidebar on his site that says "Taking my cue from Alberto Gonzales, I've dumped of [sic] a few items on the site that I felt were not loyal to my cause." Hey, at least now we know where they go for inspiration.
I don't know if this guy is one of the actual censors, but I do know that when I emailed firstname.lastname@example.org to ask (politely) about my comments disappearing, I never received a response. They clearly like the communication path to be one-way.