[melling]

It often gets referenced. You probably just never noticed. Ever watch Dead Poets Society? The common message is used in one of the scenes:

http://youtu.be/68SLg5ofQMI

About 1:30 in case you miss it.

[jandrese]

Once you know the poem you'll start seeing it in a lot of places. If you don't know the poem than it really isn't a surprise that you have not recognized it anywhere.

[andreaferretti]

Yeah, I never noticed this particular reference, not knowing the poem itself