The following question has generated some controversy regarding whether it is on-topic. (Edit: The question was subsequently moved to Math Overflow, having been closed here.)
The argument that it's on-topic is that it's related to the advising of students, in this case Ph.D. students. Here are some other possible questions about student advising:
What should an undergraduate math major do to prepare for being an actuary?
Is it better for a potential biology major to take AP Calculus or AP Statistics?
Are there certain courses that an undergraduate student should take before applying to graduate programs in operations research?
Is there any reason for a math Ph.D. student to do a postdoc if they eventually want to teach at a small liberal arts college?
See also several other questions that have been asked under the "advising" tag. So my questions are:
Are questions about student advising generally on topic?
If so, is there anything in particular that makes the linked question different?
Note: As quid points out in the comments to the linked question, the following meta thread is also related: