U.S. Patent Nos. 6,829,634; 6,701,344; and 6,714,966 are directed to broadcast channel overlays in a point-to-point communications network (pages 2-3). The “participant” is not specifically “an application program that interacts with a logical broadcast channel which overlays an underlaying network” as the claims and specification do not define or expressly describe the term in this manner (pages 6-7). “Game environment” and “information delivery service” are in the preamble but are not limitations despite there being no transition wording since they merely describe intended use without imparting structure or serving as antecedents (pages 7-8). On-line technical reports indexed by author or year only or found by a search function that did not work are not publicly accessible and (pages 11-13).
Hindsight: An express definition of a claim term may have resulted in validity, but it would be hard to predict the needed definition and may be overly narrowing for infringement concerns. It may be best to keep the preamble short, such as not including any terms for intended use to avoid debate. A transition may affirmatively delineate the preamble from the body of the claim. Consider the availability of articles beyond mere indexing to determine what is and is not prior art.