Today, someone in the forums asked if there was a way to track the yarn shops that she has visited in her travels.
There is! Every shop page has an "add to favorites" button, so you can add shops to your favorites, include them in bundles like "Visited" or "Want to Visit" and include comments. The yarn shop search can be found on the "yarns" tab.
I still need to move the Yarn Shop search so that it has filters like the other advanced searches ("near me", "purchased yarn at", "in my favorites", and "staffed by friends" might be good ones) In the meantime, if you want to build a list like this, you can use this link to see all of the yarn shops that you have purchased project or stash yarn from: