Poets, poets, everywhere

This semester I'm taking English 226, which is the survey of English literature 1700-present day. Basically that means a lot of propaganda and even MORE poetry. I feel like it complements Techniques of Poetry really really well; I get to see poetry from several sides, learning about the significant historic evolutions it has gone through at the same time as learning how it is shaped now. One class teaches me the forms and structures; the other teaches the purpose of those.
But it gets me thinking...does the purpose of poetry change through time? Definitions of poetry seem to change every generation or so...and accordingly, the perceived purpose changes as well. Some Neoclassical poets thought that poetry existed for the sole purpose of moral instruction, and that certainly isn't the case today!! Then there are all the huge debates about the process of writing poetry, etc, etc...so what is the "point-blank"? How do we really nail down conventions? Or do we? Do we follow the current stylistic fads, or no? Or do we even think about it at all? Which stylistic revolutions were engineered (Wordsworth for Romanticism) and which ones just happened in the process of a cultural shift (Shakespeare, perhaps...?).
Basically, I'm sitting here pondering...what exactly are we creating, shaping, moving toward the future, when we sit down and workshop each other? (Although granted...is every consensus added to a movement, or do only the Breadloaf and huge-scale workshops have an affect?)

PS- the soundtrack to 500 Days of Summer has some AWESOME music. yay iTunes!!