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:* The text doesn't get cleared from the comment box after the comment is sent* 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.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.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.