There are plenty of sales tactics that work like gangbusters in the physical world, but don't hold up online. Sneak previews aren't on that list.

The most crucial thing to remember when digging a moat is building a bridge: online readers need ample opportunity to come inside, kick off their shoes and sample the goods -- even if you're going to kick them out later.

The Times gets this right by always making front page articles free, and by allowing 20 inside articles per month also free of charge. But even better than that is the big first-month sale the paper announced on launch day, emulating the initial discounts of other digital subscription purveyors like Netflix and Rhapsody. Readers can now get all the Times digital content they can eat, a $35 value, for just 99 cents during the first four weeks.

If publishers want to get online readers on the hook, they definitely can't skimp on the bait.