when someone acts like a huge asshole and abandons you to go be some girls bitch while lying like a cheap rug to cover it up. only applies if he thinks the girl is going to sleep with him but everyone knows that its never going to happen.
The state of an online forum thread which has been locked by an administratior or moderator on the basis that the subject matter is too trivial to warrant further discussion. Typically a concluding post is made by the moderator to the effect that the discussion to date has made a "mountain out of a molehill" before the thread is locked for further discussion. Threads tending towards criticism of the moderator's organisation may sometimes be pre-emptively molehilled to avoid further negativity to propagate.
Poster1: Hey, respond to my post about Germaine Greer's new book!
Poster2: I can't. It's been molehilled.
While our lifespan is the number of years we will live, our healthspan is the number of healthy years we will have and our sexspan is is the number of years we will continue to be healthy enough to continue having an active sex life.
A lighthearted reaction upon receiving disappointing news of some sort. Usually something that isn't a particularly a big deal, esp. when it primarily affects someone else - sort of a mild schadenfreude. Sometimes doubled or tripled, and possibly said in a sing-songy voice for added comedic effect to imitate a muted trumpet, which is how the meme originated.