The Other Traffic Source in Google Analytics?

This week at work, one of our clients was asking what the “other” traffic source in Google Analytics (GA).
There’s not too much detail in the actual interface for Google Analytics so you have to do some digging. Traffic sources are also known as the medium in GA. I did some digging and found that Google Analytics captures the medium automatically for some other mediums, the most prominent being email.
.
This can be a very useful tool. If you’re utilizing email marketing to drive traffic back to your website, you can measure how well you’re doing by adding a querystring that specifies the medium:
https://martech.zone?utm_medium=email
There are quite a few parameters available if you wish to measure your campaigns.