You may or may not be surprised to learn that WP Smush.it is an image optimization plugin for WordPress that uses Yahoo! to run its services.

With the popularity of WordPress and the plugin — which is at time of posting active on over 300,000 websites — it is safe to say that Yahoo!’s servers were getting taxed to perform the operations on your images.

In fact they were getting taxed so much that there is concern that the server load is too much for Yahoo! to continue with the service it offers. It is time to look for alternatives before it becomes difficult to optimize your images.