I think this is mostly a US thing. Why use yearly salary? You're not paid once a year, are you? Most likely once a month. Referencing monthly salary makes much more sense.
"I'm making 50k". Great, now I have to guess - dollars? Monthly? Yearly? If yearly then what's the monthly paycheck? Net? Gross?
Many US jobs are based off an hourly rate, some with overtime (usually not added in). I noticed other posters mentioned Xmas bonus. As an hourly worker I received a standard 3% yearly raise to cover increased costs of living. Because our cost of living increase was nearly double that, our salary actually declined. Oh and that Xmas bonus... If you count a 25$ gift card to Walmart a bonus...
Pretty shit, but it could be worse.