> So, how come Ruby is more marketshare than, say, SML?
How much of that still applies if you take away Rails (and all the marketshare that came from it, and all the resulting tools, etc.)? Having a killer application makes a big difference.
The killer application of SML seems to be teaching, and awesome compiler research. With all due respect to SMLers, that's much less likely to interest hordes of average web developers.