To do something in a calculated, planned, or skillful way. Usually in shooter videogames.

The guy who says "we get signal"

the man in charge, the man who gets things done, more like the main man.

A person who loves flirting and leading people on. They are really good at this because they are very good at changing and controlling variables in different scenarios. They "operate" the way things happen around in a way that benefits them.

One who runs equipment to move dirt

A segment of DNA which helps control gene expression in prokaryotes (i.e. bacteria and such).

Derived from OP meaning Original Post. OPer, when used on internet forums, means Original Poster - meaning the person who started the thread.