My 16 year old shops traffic dived about 50%. It's on a pathetic level now. I have a few affiliate stores where the same happened as well. I don't see any major issues posted in the big seo forums. Anyone know?
It would help more if you share the name of your website so we can have a look. Have you changed anything on it around that date? Or maybe you did not change anything for a long, long time? Do give a little more info and hopefully we can be more useful