Posts, comments and threads in forum websites, homepage of newspapers, shopping items, real estate listings: these are all examples of webpages where same url might get to different content in different days, and at the moment Recall just saves one version of it, without chance to add further versions. Now the only way to capture a new version of a url would be to delete the previous card associated with that url and to create a new one from scratch, but it would be much better to have a way to save all the different versions in same card.