Domains like medical diagnosis, or diagnosis of problems with cars, are where most of the initial high-payoff applications are likely to be. Barry Silverman suggested that there are many government databases with real discovery problems. For example, IRS databases contain many interesting patterns, although some researchers may not want to work on them on the grounds of the Fifth Amendment. The FBI has many years of records of all airplane crashes. Analysis of this database may contribute to improved safety in the air.
Many corporate databases are also good targets for discovery, with numerous such projects underway.
Finally, I asked the panel to describe good and bad directions for future research. Quinlan said that there are many interesting directions, e.g. incremental algorithms vs batch algorithms, very fast algorithms. Almost anything in this area has some substance. A bad direction is to prove that some algorithm is better than ID3. A more serious example of bad research is trying to show how to squeeze out the last half of one percent of performance.