arstechnica.com article "IBM sues Groupon over 1990s patents related to Prodigy" [1] from March, 2016 includes some more details and links to 4 patents:

- US5796967 Method for presenting applications in an interactive service https://patents.google.com/patent/US5796967

- US7072849 Method for presenting advertising in an interactive service

- US5961601 Preserving state information in a continuing conversation between a client and server networked via a stateless protocol

- US7631346 Method and system for a runtime user account creation operation within a single-sign-on process in a federated computing environment

1. https://arstechnica.com/tech-policy/2016/03/ibm-sues-groupon...