I recently started using Hoptoad to in my ruby/rails projects that notifies you of any exceptions that your app throws. Unlike other solutions such as the exception notifier plugin, if an error occurs hundreds of times you just get 1 email to let you know. You can then login to Hoptoad and set it to resolved.
I thought this would be also good to use in PHP applications as well and they do provide an API for you to use. I found a project on Github called php-hoptoad-notifier by Rich Cavanaugh. I gave it a go but it relied on a couple of PEAR packages being installed and as I don’t fancy installing them on lots of servers. Iv forked and modified it to be its own standalone code base. It now just relies on the PHP curl module.