A track is a sequence of related convention programming events held sequentially, often in the same room or rooms that are reasonably close to each other. The term is used when such "tracks" occur in parallel with one or more other such sequences, which are then known as "alternate tracks."
The idea is to keep panels about the same general subject area, such as fanzines or science, which presumably attract the same audiences and draw from the same pool of speakers, from conflicting. It also allows appointment of subject experts to develop a set of programs and can make room allotment and scheduling easier. The drawbacks are that tracking discourages fans with disparate interests from meeting and mingling with each other, and may prevent those from branching out into other interests; it encourages duplication of program items where there is overlap; and con goers with wide interests will have conflicts anyway.
Conrunners also use the term informally to refer to different areas of subject matter even when not doing rigid tracks.
Contributors: Dr. Gafia, others.