I went into undergrad with a primary focus on (meta-)logic[1] and I was taught by some of the world's premiere logicians (David Kaplan, Sam Cumming, a few others). But I fell in love with ethics -- a subject I'd never thought I'd enjoy as much as I did. I loved reading Moore, Foote, Anscombe, Geach.
My best memories were attending graduate seminars -- studying the philosophy of language and trying to figure out how logical connectives work in regular discourse, or studying abduction and trying to stitch together Horn clauses that seem to point to one conclusion rather than another.
Philosophers, in short, do all kinds of things: from pushing the boundaries of exotic logics, to solving ethical problems, to systematizing natural language or understanding the metaphysics of causality.
The article just touches on all of the above (in fact, it doesn't discuss modern philosophy at all). If you're interested in philosophy, the SEP[2] is a great resource.