I am thinking of creating a simple web based instant messaging using a combination of PHP and SQL. To keep it simple I was thinking of not sending the message to the other clients browser using COMET or AJAX, but simply uploading it to a SQL database. The other clients computer will then periodically refresh the webpage which will cause the PHP code on the server to check for and return any new messages.
Would this method be simply to slow to be actually useful? Thanks in advance :)