I use utm code to track my campaigns. However, I enabled the marketo tracking and mkt_tok on my links instead and now the reporting on Google Analytics has over 700 url variations for my email. My question is what is the marketo tracking used for and if I disable it will it affect my analytics in marketo?
If you turn off the mkt_tok you will no longer have web activities (Clicked Link and Visited Web Page) associated with your leads unless you can convince them to fill out a form on all of their devices. That's the simple -- and quite catastrophic -- side effect.
A few of us have written about how to filter reports in GA, such as here: https://nation.marketo.com/message/167078-re-removing-mkttok-from-an-email-link-tracking#comment-167078