referals are the people who have joined DC by clicking on a specific type of link that you provided to them. Its not really that important. 99% of DC has a 0 on referals since nobody knows what the link is and it doesn't really matter anyway. I've brought dozens of people here, but I didn't do it so I could see a number by the referal thing.
User notes are just comments that you can leave for people. Again, it doesn't matter and I haven't ever seen anybody who has used it. When you click on the 'view' under the notes it gives you the option to post something. I really haven't experimented with that at all and I have no idea if the notes are public or private. I would just suggest using good judgment when you test it.
