In a new post to her blog Maggie Nelson points out the importance of error logs and a handy tool Zend Framework developers can use to make FirePHP even more useful.

The error log is a standard development support tool. It will help you find problems with your application. When developing, I take extra care to make sure that the error log is clean - this includes warnings and notices as well. When your application gets deployed, you can then depend on the error logs to accurately report any issues. [...] On a recent project, my coworker Matt Purdon wrote a pretty awesome debug console that leverages FirePHP support in Zend Framework to log a lot of information about what the application is doing directly to the Firebug console.

The end result is a console that lets you track things like session variables, memcached information and queries executed in the request (with explain plans). You can see a screenshot here.