Last night I made several posts to this thread using Mac OS 10.9.2, Safari and FF 26.
I did not encounter any problems.
When I finished, as no one else had posted, I deleted them using "delete" on the first post of those posts. The prompt offered to delete all my posts from that one to the end - I did this for both gleng and was_gleng.
This morning Communications is still showing a couple of the deleted posts with the following content:
"The information you are looking for may have been moved, you can search for it here. We apologize for the inconvenience."
Do see any of the deleted posts in your stream?
Comment - Chrome
At this point FF was unable to post and is showing the grayed out Comment button. It looks like the browser session is otherwise unaffected. I can scroll around, the unopened Communications count is updating, I can still edit the unposted message, the Cancel button looks active. I will let it sit for awhile ...