For example, on a travel Web site, users can book airline tickets and car rentals without having to sign on more than once.

To find such places, don't ask the concierge for advice, but chat up a local storeowner, rental car clerk or hotel maid, or visit social review websites such as Chowhound or Yelp.

Ancillary items such as airport parking, car hire, holiday insurance and excursions are also available from the MyThomson service and all quotes are tailored to the customer's local details.