In the period after this was posted, only Spammers and Geeg were able to post for about 2 hours... Maybe Yahoo allowed Geeg because he is a spammer... or not.
There's now an article on CNBC about the Yahoo website outage. Remarkably enough, it isn't covered anywhere else. Anywhere. Trying to Google it. Or try searching on it from Yahoo's own home page... You won't find links. A CNBC exclusive story? This new partnership between Yahoo and CNBC is rather remarkable...
If you read Sybil's and Techstrategy's recent posts, you know they're deeply disturbed, deranged individuals. As such, they are paranoid as well. They think their posts are so significant that Yahoo censors them to protect AMZN investors (longs). How delusional and paranoid can one get? Their being stuck in the latest losing battle for almost a year has taken its toll.
As to Sybil being banned by Yahoo is possible, not due to the core meaning of his posts. His language was bad. Some were explicitly racist messages,)
I forgot to mention that Yahoo's new message board system is extremely buggy. Their messages may have been just lost due to some system failures. If they think the system is working flawlessly, they're deranged. (Or simply stupid.)