It has been quite a long time since I last looked into Franz' licensing terms, but I believe the royalty applies only if you distribute a product which contains the Allegro CL runtime. In other words, if you write a Lisp application, using Allegro CL, and you deliver it to a customer, then the customer effectively has a copy of Allegro CL. Franz wants to be compensated for this. If you wrote a server-side product, then Allegro CL is expensive, yes, but you just pay for the number of licenses you need. No royalties, as far as I know.