I believe IBM's business model is based on servers and main frames for business applications (banks, retail stores, etc.). IBM's problem is that the Mac is a three stream machine:
1) Desktop data processing for baks, retail stores, management of a variety of systrms, etc.
2) High speed scientific/engineering clculations such as weather forecasting, real-time problems, nulear weapons simulation, NASA simulations (orbit, etc.)
3) Portable versions of 1) and 2).
I suspect that IBM worries about all three areas that comprise significant financial streams. If the gentleman in question has deep planning knowledge then IBM should be worried.
There is precednce for this kind of situation in a similar case in the 60's. A good year senior engineer at Goodyear rubber announced he was moving over to the competition, Goodrich rubber. Goodyear had all the patents on the astronauts suits worn by NASA flight personal in its moon landing program. The engineer could take over to the competitor proprietary information that would affect Goodyear's competitive position. If I remember correctly, Goodyear's suit against Goodrich was dismissed by the courts. (Note, I may have Goodyear and Goodrich inverted.)
MamaMoose