I've mentioned quite a few times that I am a big fan of Perl programming language. However, most of my programming time these days is spent in PHP. The languages are often similar, with PHP having its roots in Perl, and Perl being such a influence in the world of programming languages. This similarity is often very helpful. However there are a few difference, some of which are obvious and others are not.

His example compares looping (a foreach in both) and how, after the Perl loop the $value variable is no longer accessible. In PHP, however, it's passed back out into the current scope and can be read just like any other variable. While this can be useful, it can also cause headaches when trying to track down elusive bugs.

The job of approving comments sometimes falls on a person who does/should not have access to the WordPress admin. By design WordPress only allows a user with admin privileges to do this job. I wrote an an External Web Interface for approving pending WordPress comments via XMLRPC.

You can download the source from the Google Code site for the project and check out a screencast in his blog post.

The most secure application is one with no connection to the outside world.

As we've covered, you can't really disconnect the network from your web server if you are building web applications. You can however, carefully consider which servers need to be connected to the outside world and which can be inside your firewall. Beyond that, you can also evaluate how those servers that have to remain outside your firewall communicate with the ones inside.

No, his suggestion is not to take your application "off the grip" but more to limit access to things like database servers to help protect the data that lives inside it.