Out of curiosity, do utm tags still offer much value beyond standard Google Analytics? I remember them being popular back in the pre-GA (Urchin) days. Since GA already tracks referrals coming from email, social media, web, mobile, etc.; perhaps the major benefit is tracking a specific campaign that is already a few steps removed from the initial referral.
There are a lot of use cases where they're still quite valuable.
- Social sites tend to redirect outbound links to sanitize referral information. So you can get a bunch of traffic from Facebook, and have no idea if it's people viewing your page, going through their news feed, postings in Groups, etc. All of your Facebook traffic will have a referral of (l|lm|m|business|mobile|web).facebook.com/(l.php)? [1]
- Unless someone is using a web client, any clicks from email will show up as direct traffic, just as if someone typed the url in their browser directly. So you can't evaluate email performance in GA without dedicated utm parameters.
- The Source field in GA defaults to the referrer, but is overridden by any explicitly provided utm_source data. If you capture the true referral information separately (i.e. put the value of document.referrer into a custom dimension), you can compare the two and glean all kinds of nifty info like traffic from Site B and Site C resulted from a link on Site A.[2]
- The concerted effort to upgrade sites from http -> https has led to increase in traffic marked as direct that's not direct, because of referral header stripping. Note that it's not inherently an issue with https itself, but with the fact that not everyone is using https yet, combined with the cumulative number of pre-existing http links.[3]
There are plenty more, but those are some of the bigger things I can think of off the top of my head where standard GA falls short and having utm-tagged links are beneficial.
[1] Yes, I'm aware that this regex is lacking escape characters. But having them reduced readability.
[2] If someone takes a utm tagged link from Facebook and shares it on Twitter, by default it'll look like it came from Facebook in GA. Unless you're capturing the document.referrer value manually in a custom dimension, you wouldn't be able to suss out that this was happening and would never know that they're actually coming from Twitter based on a link you shared on Facebook. Or even that they're coming from Twitter at all.
utm tags let you run 10 different social media campaigns and compare them to each other. GA by default will only show you a social media total, not split into the efforts by Alice's botnet, Bob's human retweet club, and so forth.
