TINA BROWN’S talk show on CNBC, which debuted last night, happens only four times a year. Therefore, it might compare with a daily show the way a quarterly journal compares with a newspaper, the former being deeper and less on the cusp of the latest news story. Only it’s not deeper than your average talk show. Still, it’s not too bad if its pretensions don’t rub you the wrong way. The basic format is generic, although the show proves to be otherwise. The former queen of buzz sits on one side of the table and chats with her famous and almost famous guests (two at a time), who make up a rather effete roster of smart, beautiful, and rich personages. Indeed, there is something almost Victorian about Ms. Brown’s invite list. There is a very smart writer from a fashionable magazine talking with a strapping captain of industry, and then we are treated to the chatter of a celebrated historian as he makes nice with the queen of Jordan, the whole cast rounded out by an important press baron with the most biting wit and yet another influential businessman whose contacts in Asia are the very best.