When employers list being proficient with Microsoft Word and Excel, what exactly do they mean? In other words, does someone have to know all the tricks and shortcuts of the applications or does it mean something different?

Proficient: Well advanced in any branch of knowledge or skill; possessed of considerable acquirements; well-skilled; versed; adept,

Source: Webster's Revised Unabridged Dictionary

It's a subkective term, but in general, they're usually looking for someone who's comfortable and knows their way around an application at an intermediate level, but less than what would be considered advanced or expert. 

They're not looking for someone who knows tricks and shortcuts.  They're looking for people who know how use an application to its potential and for what it was designed to do.

In Excel, knowing how to create advanced formulas and functions and creating pivot tables would be considered proficient.

Good luck and all the best.

If you know computers enough to --- OK, you're online so you know as much as you need to to start ---  just get a book like Excel or Word for Dummies or something that says you can learn it in 5 days and you should be set.  If you don't have access to those programs at this point, you can go to the library or join a temp agency that has a computer lab.  Temp agencies sometimes also have tutorials that can teach you those programs.  Also, check with your local library to see if they have free courses. 

Best of luck!

Good public libraries even have the latest 2007 self taught books.  No need to buy new books.