if your view is about market as a whole (Europe/IT slowdown etc), use the right instrument to express your view.
if your view is about the company, then hedge the proportion that is too big, and keep some direction exposure.
if you still like the company - say you think your FB on hand will outperform GOOG - then keep your FB and sell some GOOG.
do not take unnecessary risk. find the instrument that expresses your view.
have said all these, we tend to exaggerate our edge in companies stocks that we are familiar with.
just my 2c.
