  We discuss three different observational diagnostics related to disks around
hot stars: absorption line determinations of rotational velocities of Be stars;
polarization diagnostics of circumstellar disks; and X-ray line diagnostics of
one specific magnetized hot star, $\theta^1$ Ori C. Some common themes that
emerge from these studies include (a) the benefits of having a specific
physical model as a framework for interpreting diagnostic data; (b) the
importance of combining several different types of observational diagnostics of
the same objects; and (c) that while there is often the need to reinterpret
traditional diagnostics in light of new theoretical advances, there are many
new and powerful diagnostics that are, or will soon be, available for the study
of disks around hot stars.
