Etapestry shows accounts with different addresses as duplicates when you only use 'address' for the key. For example, it shows 1234 Easter Seals, Houston, TX 77027 and 1234 Valley Forge, Houston, TX 77024 as duplicate accounts even though the addresses are entirely different. I am aware that you can add another key and that it might help with this issue; however,  the problem I have run into with using multiple keys when doing a massive import, which we do yearly for an event we have, is that you end up with a ton of duplicate accounts because it only pulls those that match every category (i.e. address & email) when some are the same account we just don't have an email for them or they use a different email.