Comments are getting deleted for some odd reason. Also I am getting a ton of emails saying Wordpress is giving an error when you try to leave a message on a post. Server is working on this as we speak.
Sorry for the inconvenience.
UPDATE from server ppl:
Vera,

I have located a large number of comments in the database that have a date in the future. This causes the comment not to be posted until after that date has passed. It is also (from what I have read) responsible for the error you and your users are seeing about posting too fast.
mysql> select * from wp_comments where comment_date like '2012%';
1334 rows in set (0.18 sec)
That's a lot of comments that probably didn't make it to your site! It seems as though these comments with the incorrect timestamp are not just from the past few days but have been spread out over a fairly long period of time. I am currently trying to figure the best way to fix these timestamps. I also will let you know why this has happened as I research a bit more.

Update II: Should be fixed (it's 4:30 PM). Let me know if you see a problem