I don't have more than a few minutes spare seems like atm, but I am adding a ton of books to my ever growing TBR list, because when I do have a bit of time over, scrolling through reviews on BL is a great relaxing way to use it.
I'm also always forgetting why I added a particular book, or who recommended it, so the new private note feature is perfect for this.
Grab the url of the review by right clicking it and choosing "copy link" right on the dash (or just go to the review page and copy it from your browser) then add the book like normal, and drop the URL right into the private note.
And in case you missed the announcement, or already forgot how to activate it, it's here on the book page, over on the right of the top panel:
That'll drop open a new pane beneath the "Want to read" etc buttons, which is where I'm sticking the review link (or a note who recommended it to me if it wasn't a review).