Hm... perhaps you're just not as familiar with advertising/marketing as you think? There are tons of English majors who write ad copy. Case and point: http://en.wikipedia.org/wiki/William_Bernbach
William Bernbach, founder of DDB, famous copywriter, and... drumroll please English major. Note, this is just a famous example I knew off the top of my head, but if you go look on LinkedIn there are tons of people in the ad industry with English majors.
When patio11 mentions literary criticism I take him to mean what goes by the name English major today. We can be pretty sure than what those two did in their majors in the '20s to very early '30s was very different than what many if not most do today.
Even if it's literary criticism, for today that's mostly done in a way that's much less broadly focused, right? E.g. who outside of academia and some narrow related circles cares about deconstruction? (Admittedly, some of that is due to cultural changes where literature has lost a tremendous amount of "market share" to modern media starting with movies and radio.)
William Bernbach, founder of DDB, famous copywriter, and... drumroll please English major. Note, this is just a famous example I knew off the top of my head, but if you go look on LinkedIn there are tons of people in the ad industry with English majors.
Here's another famous copywriter/English major: http://en.wikipedia.org/wiki/Fairfax_M._Cone