> It appears that only about 10% of all LISTSERV(R) lists are public

That sounds about right. There have always been more private than public lists, except perhaps at the very beginning.

> Only about 10 lists have 100k or more subscribers

Sites with large newsletters almost always run in standalone mode or behind a firewall and aren't on CataList at all. They want people to subscribe via their web site, not via CataList or any other tools. I also think that large newsletters are going more and more in the direction of opening an account at the company's web site and checking "Please send me the newsletter" in your profile options. In this case the membership is stored in a database rather than in a list file. LISTSERV is used to send the messages and process bounces. The bounces may not necessarily trigger a traditional SIGNOFF, they may instead mark the e-mail address itself as invalid (which does have the side effect of stopping future messages). You might see this as an action request the next time you log in to the web site - please give us a new e-mail address that works.

  Eric