They are definitely different things, and yes, both should be set.
"Identify the channel as" is where you set the Channel to one of your specified channels (these are your high level groupings - i.e. Paid Search, Organic Search, Social Media, Paid Social Media, Emails, etc). This will populate the dimension Marketing Channel
"Set the channel's value to" is where you set values that will help you drill down more into the details of the Marketing Channel. This will populate the dimension Marketing Channel Detail. What you set here can change depending on the Channel and context.
For instance, for Paid and Organic Search, I might want to set the Detail to "Search Engine" so that I can break down my Search Traffic to Google or Bing or Yahoo, etc.
But when it comes to my Marketing Emails I might want to set the detail to my UTM_Campaign value or my full Tracking Code (based on all UTMs mapped into one string) or my CID (which is generally going to be Tracking Code when using one CID instead of multiple UTMs).
What details you map will be up to you, but should provide you details for drilling deeper into your Marketing Channels.
Now, you might be thinking, why do I need to set the "detail" to my Tracking Code dimension, I already have that.. I can just correlate it?
The answer to that is "different attribution". Tracking Code is generally set to a 1 Week Attribution, whereas Marketing Channels are set to 1 Month by default, and while yes you can change these, you have to keep in mind that when it comes to processing things might not match up...
For instance:
- Visit 1
- Google Paid Ad: utm_medium=cpc (for instance)
- Marketing Channel = Paid Search / Marketing Channel Detail = ad12345 (using UTM Campaign in the mapping)
- Tracking Code = "cpc|ad12345" (utm medium and utm campaign)
- Visit 2
- Google Organic Search: no UTMs
- Marketing Channel = Organic Search / Marketing Channel Detail = "google" (set to "search engine")
- Tracking Code = (nothing is set) so "cpc|ad12345" is carried forward with 1 week attribution
When you look at Conversions made in Visit 2, if you look at your Last Touch Marketing Channel and Marketing Channel Detail, it will be "Organic Search from Google" (no UTMs)
If you look at Tracking Code, the last touch tracking code still says "cpc|ad12345"
So you have a mis-match due to attribution. And while yes, the last touch Tracking Code is from a paid search, the last touched channel is not paid, it's organic.
Marketing Channel and Marketing Channel Detail are designed to be in sync with one another, to ensure that when you drill down your values, you are looking at comparable data.
Marketing Channel and Marketing Channel Detail can also have Classifications applied, so you could set a large all in one eVar with many values into your Detail and use classifications to split it into individual pieces that you can build into rich results.
I hope this helps.
