As technology evolves, the definition of "programmable" analog/mixed-signal ICs has evolved as well; most users find the change to be a very good thing, despite any limitations it may impose.Amplification, Conversion, Integration Nation, Power
Whenever I see a new product announcement saying an analog or mixed-signal component is "programmable," my first thought is simple: "in what way?" Often, it's not called out clearly or until the end of the press release.
The reason I wonder is that "programmable" is a term that can take on many different realities. Back in the day, a programmable IC (such as an op amp or filter) was one where the user could set the gain, cutoff frequency, or other characteristics via external resistors. Soon, IC vendors incorporated these resistors inside the device, so the programmability was done by jumpers on the PC board.
There were pros and cons to this setup: On the pro side, lower total cost and a simpler BOM (no need to get your own resistors, which usually had to be tightly matched for best performance). On the con side, you were limited in your settings of gain or cutoff. For most users, the choice was easy: Using internal resistors with fixed settings was a very acceptable restriction versus the benefits.
Click to see the slides, the article on Planet Analog.