Hey PC, the escape filter is used to swap out certain characters with HTML code. For example, if you have a quotation (") in your link title, it would replace it with a ".
This is "my" link title
Would be:
This is "my" link title
It's handy for when you're outputting a string within an HTML attribute because if you don't escape it, the attribute may be closed prematurely.
I hope that helps!
tetchi