Is it just giving different names to previously named method? Does it change with the language you use? Is it essential? I have noticed different APIs having deprecated methods, which actually seem easier to use.
3
It usually means that any code marked as deprecated is considered old and out of date, or it may have potentially serious issues with performance/conformity to standards/platform-specific issues/security/compatibility/etc…, and that there is probably a better replacement. It is marked as deprecated to indicate that developers writing new code should avoid that deprecated code, but it is left in the API so that old code that was written before the code marked as deprecated will still function without needing to be re-written.
2