Like is, like, focus

by Underhill

Like "functions with great reliability as a marker of new information and focus."

It also introduces new concepts or entities, marks focussed information, marks the focus in questions, marks the answers to questions, can be used as a hedge, sets off unusual notions (not meant to be taken seriously), sets off stereotyped expressions. It can also be sentence initial.

It could have derived from the use of like to mean for example.