Comfort of Bloated Web
I'm sure OP is getting lots of comments now!  I'm not sure the rapid timing is really the cuprit here.  I would argue that there are other UI factors at play:<p>* The text doesn't get cleared from the comment box after the comment is sent<p>* The submit button has no visual affordances to indicate whether it is valid.  It looks exactly the same when the form is populated or empty.  A conventional UI approach would inactivate the submit button until all the fields are filled.<p>So despite the message that the comment has been posted, it doesn't appear as if the state has changed as a result of pushing the button.<p>I think clearing the comment box and inactivating the submit button (which doesn't appear to be a native OS UI element) after submission would help users understand that the state has changed.  Alternatively, I think displaying the acknowledgement message on a new page with no submission form would achieve something similar.  It could even have a "post another comment" link back to an empty comment page.