In the advanced tab I see Campaign Tracking within URLs: In Anchor vs In Parameters. What's the difference between these two options? Would one of them explain why UTM codes seem to get tacked on to some URLs when I receive notification emails?
Google Analytics allows for campaign tracking data to be done with anchors or parameters. So it's the difference of your URLs looking like: https://example.com/?utm_source=newspaper&utm_medium=banner&utm_campaign=product (parameter based) vs. https://example.com/#utm_source=newspaper&utm_medium=banner&utm_campaign=product (anchor based)
Yeah... since anchors aren't sent to the server on an HTTP request, you can't alter the page based on them (unless you do it client-side with JavaScript or something similar). There are benefits to doing it both ways... parameters can be seen by your server, so if you do secondary tracking on your server, you would want to use them. Anchors could have a SEO benefit since Googlebot treats them the same with or without the anchors (again because they are client-side only). A parameter in a URL makes the URL unique as far as Google is concerned (so if you had a bunch of incoming links using tracking codes, it would be better for SEO to have them all treated as the same URL).