Even a single visit can prompt the creation of a computer file that includes diners’ allergies, favorite foods and whether they are “wine whales,” likely to spend hundreds of dollars on a bottle. That’s valuable information, considering that upward of 30 percent of a restaurant’s revenue comes from alcohol. Some places even log data on potential customers so that the restaurant is prepared if the newcomer shows up.

Much of this information is discreetly embedded in an alphabet soup of acronyms that pops up on the computer screen when a restaurant employee checks you in, managers and employees at a number of high-end New York restaurants said in interviews. The wine whale may show up as WW. If a free appetizer lands on your table at Osteria Morini in SoHo, chances are your file says SFN — something for nothing.

The restaurant may have given you the freebie because you are a FOM (friend of the manager) or a PX, a person extraordinaire. PX used to be V.I.P., but most restaurants stopped using that label years ago because it was so widely recognized and offended non-V.I.P. customers who heard it being used. Some PX’s are also flagged NR, for never refuse.

At some restaurants, HSM is short for heavyset man; at others, LOL stands for little old lady — two types of diners who may need special seating. Customers with bad reputations are often flagged HWC, handle with care. And if there’s an 86 on your profile, chances are you will be making alternative plans for dinner.