Driving this growth, of course, is digital content. It’s hard to measure just how much content is now stored on home computers, but based on reported activity, it’s certainly on the rise. A Forrester Research survey shows that the number of people viewing or managing photos on their computers rose from 26% of survey respondents in 2002 to 47% in 2007. The percentage of those owning an MP3 player went from 3% to 36% during the same time frame.

“The digital assets that people have are clearly climbing, and with that comes the potential need for a home server,” analyst J.P. Gownder says. Diffusion Group senior analyst Ted Theocheung notes that the average computer user will have up to 2 terabytes of content stored by 2010.

But increased storage capacity is not enough to jump-start the market. The real appeal of the home server is its synching, streaming and management capabilities. The more devices in the house that need access to the same content, the more need there is for a home server.

According to Forrester, the number of homes with multiple computers increased from 25.8 million in 2002 to 47.8 million last year. These computers are increasingly being connected via a home network, the penetration of which has doubled in the same time period from 12% to 24%. And that’s not even including the proliferation of iPods, mobile phones and other portable devices that need access as well.