<p>I keep seeing references to the visitor pattern in blogs but I've got to admit, I just don't get it.  I read the <a href="http://en.wikipedia.org/wiki/Visitor_pattern" rel="noreferrer">wikipedia article for the pattern</a> and I understand its mechanics but I'm still confused as to when I'd use it.</p>

<p>As someone who just recently really <strong>got</strong> the decorator pattern and is now seeing uses for it absolutely everywhere I'd like to be able to really understand intuitively this seemingly handy pattern as well.</p>

The reason for your confusion is probably that the Visitor is a fatal misnomer. Many (prominent
1
!) programmers have stumbled over this problem. What it actually does is implement
double dispatching
in languages that don't support it natively (most of them don't).
1)
My favourite example is Scott Meyers, acclaimed author of “Effective C++”, who called this one of his
most important C++ aha! moments
ever
.