beware of many ajax calls and database writes

I was just called in to troubleshoot a site that was consistently crashing a client’s web server. It turns out this plugin was triggering an ajax call every 2 seconds for each connected client. Because each call was writing to the database, no caching was happening and each call was taking 400 – 500ms to process. On the client’s VPS, more than 20 or so simultaneous visitors was enough to take the server down (4GB RAM VPS).

I can only imagine the havoc this would wreak on a site with medium to high traffic!

So if you’re thinking of using this plugin, and you expect more than very light traffic, I would highly advise looking at the paid option to move the callbacks to a hosted service, or have a look at other hosted services that provide similar functionality.