Glue That Doesn't Set

Dave Thomas posts about how Perl and Ruby are like glue that connect things together on the internet. The problem with Perl, he conjectures, is that it "sets". When you read Perl, especially if you didn't write the code, it's difficult to discover what is going on and therefore difficult to modify. Now, you can write obfuscated code in any language, but I'd have to agree that Perl has a propensity toward poor readability. What's interesting to me is that Ruby is described as the "Glue That Doesn't Set" or the code that is always easy to read and understand the intent of the author and on top of all that easy to modify. That's pretty high praise if you ask me. I wonder if it's more the conventions and included libraries (Rails, in this case) that make this so, and less the language itself. It's an interesting metaphor anyway.