The MCP3021 is a standard 10-bit ADC with an I2C Interface. It's datasheet can be found here.
In the general description, it says:
The device is also addressable, allowing up to eight devices on a single 2-wire bus.
What does it mean to be addressable, how are devices addressed, and why does it say only 8 devices are allowed on one bus? Shouldn't it be much more?