What Roogna said. If you'd like some help identifying the artists, you can always post a thread here with pictures.
I have a Word document with a list of all my customs, including the pony's name, the artist's name, how I ended up with it (e.g. swap, gift, purchase, commission) and the year I received it. I don't have a large collection yet so I think I would still be able to identify the ponies without the list, but I'm anticipating it'll get harder and harder in the future... and I'm hopeless with the ponies' names!
It's handy to have all that information in one place in case I ever need to sell some of the ponies.