I'm not sure they have to do much 'selling'. They had a product on the market at the right time to become 'the' solution for computational math. As with many

I'm not sure they have to do much 'selling'. They had a product on the market at the right time to become 'the' solution for computational math. As with many applications or languages (or, in this case, both), being exposed to it at the right time creates a client for life. Those lifers become evangelists in the same way lispniks do (and watch out for those of us who are both), requesting that employers license the software. If you are between, say, 35 and 45, went to a "decent" university (i.e., one Wolfram and/or NeXT targeted), and have an applied math background of any sort (CS, physics, engineering, etc.), you were very likely exposed to Mathematica. It's just a few steps from there to having a prof use it in a lab or using it because an employer had made a previous investment in development. At that point, much as with C, or Java, or CLISP, or whatever, it becomes a fallback computational tool. SAS acquires many of its licensees in a very similar way.