Yes the above statement is pretty much correct. "Smart" is American English whereas "clever" is British English. The meanings are exactly the same.

Pri viet! Clever is a form of intelligence which means that you are quick/fast-thinker that comes up with good solutions to tricky problems. Smart is a more general term regarding intelligence, it can refer to mathematical intelligence, being good at science, etc. I think clever is somewhere between esperto and habil in Portuguese, not sure about Russian. Paca! John

I think they are synonyms. I've noticed that "clever" is more used in British english, but I'm not sure.

"smart" is closer to slang