The Wall Street Journal writes today that magazine publisher Meredith, whose print advertising has “plunged” 15 percent in the last year, has raised a successful digital ad business. Sold to the same clients that aren’t advertising in its magazines, this unit’s revenue are up 13 percent – to the tune of $175 million, the WSJ reports.

It’s a brilliant “alternate” business that’s far more successful than the main business. It clearly provides huge value to clientele, and they’re happy to pay for it.

How can you pull a Meredith? What potential parallel paths for revenue are available to you?

If you’re a former world-beater now making a struggling smart phone in a crowded and highly competitive category, can you license your excellent operating system and applications? Can Palm pull a Meredith?

If you make stand-alone GPS devices, for example, you’re in a market that will soon be saturated. What about smart phones? Sound familiar? Garmin has pulled a Meredith.

Google has pulled many Merediths.

So has Apple.

Microsoft used to.

In consumer electronics, it’s possible to get into too many categories and lose focus. We’ve seen it happen with Microsoft, and I worry that Google and maybe even Apple are headed in the same direction.

You don’t want too many Merediths, but one or two can be tremendous.