I was creating some user lists today of cards on my want lists by set and I saw on the right side of the page under the "Your Collection" heading that I already had one card. Curious, I clicked on the blue "Update Your Collection" button (which I never used before) and it brought me to a checklist of the list I had created. In the end, I figured out that I did have the card in question, but it was in my Orioles team collection, but I also need it for a set. Problem solved.
While solving that mystery, what I found interesting is there is a percentage on the right side of the page showing how much of your created list is complete. Now, THAT got me thinking! I've seen several posts here on how team collectors have a hard time keeping track of what percent of their teams sets are complete since everything here is arranged and tracked by full sets. This is a way! Put the team set in as a user list and the percentage will be recorded.
Now, is there a way to add several cards to a user list without going through and adding each card individually from the card's page? I don't think there is. If anyone has info on this, please chime in.
Thought I'd share this discovery I found today with everyone.