Use on user pages or user talk pages when people shouldn't expect them to be answered quickly. When using simply {{busy}}, the template produces the message above
There are two unnamed parameters. The first which replaces "this user" with the name placed.
IE {{busy|He}} produces
He is busy in real life and may not respond swiftly to queries.
The second unnamed parameter replaces "in real life" with whatever is put. Unfortunately, at the time being it requires for there to be something in the first parameter as otherwise nothing will be shown for the first parameter (DO NOT use {{busy||foo}}).
IE {{busy|This user|at [[school]]}} produces
This user is busy at school and may not respond swiftly to queries.
{{busy|Johnny Doe|descriptor=working|at school|image=Information icon4.svg|reason=school being compulsory|end=Saturday morning (EST)|msg=I won't be on for Saturday the 25th, though.}} produces
Johnny Doe is working at school until Saturday morning (EST) due to school being compulsory and may not respond swiftly to queries.I won't be on for Saturday the 25th, though.
Emily Smith is studying for exams until Sunday evening (PST) due to preparing for finals and may not respond swiftly to queries.I will respond to messages on Monday.