Caroline, Nope! You did nothing wrong! I've found out what the problem might be, but I'm not positive quite yet. Apparently once you go over 200 members, Yahoo puts your membership list in another category, and updates are no longer instantaneous, but are usually hourly. If they are doing some other work, the updates may take several days.
So, I'm going to try to stick with Yahoo for now. What that means is that when you join, it may take awhile before you can set your mail preference. In the meantime, you can go to the berner-l group and read the emails there on the web. You can post to the List. But you won't necessarily be able to receive email without a bit of a delay. Once everyone is on the List and we're up and running, it won't be a problem (she said optimistically), it's just the initial setup that will be a growing pain for us all. The other option is to use a different email list. Which is likely to have some growing pains of its own. I wish I could find my magic wand and convert everyone transparently, but I've misplaced it somewhere. Thank you all for being patient, we will get there!!! Pat Long (& Luther) Berwyn PA