aguahombre, on 2014-February-15, 17:50, said:
I don't understand using the cue to merely establish any old game force. Responder has forcing or nonforcing (your choice) freebids and a negative double for hands without Diamond support, (or even with Diamond support). This leaves the 2S Cue for only hands with Diamond support and not 4 hearts; does Acol not have negative doubles in the kit?
Given the origin of the term "unassuming cue bid" I would imagine Acol was one of the earliest systems to adopt the cue as promising support. Negative doubles are also standard, although many club players only use them up to 2♠ or 3♠.