Deliberate misspelling of 'yes' that originated at the Figure Skating Universe forums, often used by people who want to add a bit of wannabe "Russian flavour" to what they're writing.
Can also be used in the same way as "aren't you?" at the end of questions.

This means that you are really unhappy with someone (single person) or the world as a whole.

This word can be applied to books / buildings / vehicles / persons or groups - and you are easily able to simply point to the phrase - without even having to say anything !

The letters mean - Eat Your Shit