1.What exactly is Unearned Revenue? How would we categorize this (i.e., where would it be reported on a company's financial statements)?

2. I want to emphasize that this is not a class on taxation and payroll, but in the context of the current topic we need to at least introduce this concept while not spending too much time on it, so here's a fresh question to briefly address...

What exactly is OASDI?? (for many people, though not all, this likely impacts your paycheck)