> > I see many posts about I2C.  Not so many SPI queries.
>
> Because SPI is easier?
>
> > This leads me to suspect that I2C is more popular than SPI.
> > Why is this?
>
> Because I2C is better :)  Specifically, the fact that I2C is a two
> wire bus with no Select lines needed means that for severely
> pin-limited applications (all of them!?) you can do more with less.
>
So is DALLAS's 1-wire better yet? ;)