Lou recommends After the Dot-Bomb: Getting Web Information Retrieval Right This Time

"I explained to the broker that the idea of "push" technology was first called "selective dissemination of information," or SDI, and, to my knowledge, had first been proposed in 1961 - yes, 1961 - in an article in the journal American Documentation by an IBM computer scientist by the name of H.P. Luhn (1961). He worked out the idea in considerable detail; the only key difference was that the old mainframe computer would spit out informative postcards to be mailed to customers, rather than sending the information online - since there was no "online" to use in those days."

Which reminds me both that

innovation comes only from a deep understanding of the problem (otherwise you can fall into the trap of re-invention.)

and

those who do not learn from history are doomed to repeat it.