Right above that diagram, in the NOTES section, it says RL = 200Ω. "RL" means "load resistor". You'll see that they show it in all the other diagrams, too.
This op-amp is specified for high-frequency video applications, and in these cases you generally have low impedance loads like this so the sources and loads can be matched to avoid reflections back up cables.
In Recommended Test Procedures for Operational Amplifiers they describe using a load resistance when measuring transient response, and have a table of recommended values for each part (0.2 kΩ for this part). I guess the high-speed transient response is affected by the load (I don't work with high-speed stuff), so they're showing it in-circuit to show a real-life application.
The overall gain will also be decreased, since the output impedance of the op-amp is 25-30 Ω (as shown in page 2 of the datasheet), and the maximum output level will be decreased, as shown in Figure 13. In the application notes, it says:
In Figure 19, RIN is usually the
terminating resistance for the input
cable, and it is usually 50Ω or 75Ω .
RM is the matching resistance for the
cable being driven, and RT is the
terminating resistance for the driven
cable. RT is often shown here for gain
calculations while it is physically
placed at the cable end.
In this case, RT is the same as RL in the datasheet. So it's being shown "here" for its effect on the gain.
So, in general, they're showing the load in the circuit to demonstrate that their measurements were tested in a real-life video situation.