Say you're a Bostonian with a little extra to give—time, money or even a few Red Sox tickets. Where do you go? WCVB Boston, Hearst-Argyle's ABC affiliate, wants you to go to its Web site and click through to CommonWealth 5, a forum for Beantown charities looking for goods and services.

If you're that mythical Red Sox fan, when you get to CommonWealth 5, you post your offering (it takes about 30 seconds), and e-mails are automatically sent to 280 participating charities that might want those seats. Charities contact you, and together you finish the deal on what amounts to a kind of altruistic eBay. The Web site also has individual charities' wish lists.

Although other charitable Web sites are available, WCVB Director of Public Affairs and Community Services Karen Holmes Ward says, "This one is the only one that uses the power of television to drive viewers to a charitable-giving location." WCVB promotes the service with 50 weekly 30-second public-service announcements.

As the four-year-old service has grown, it has "matched" over 1,200 donors and charities and hired a part-time employee to work for CommonWealth 5.

The service is growing, too. It has a waiting list of about 50 charities the station will check out to ensure they're on the up and up.

"We want donors to feel comfortable" about the legitimacy of the charities on the site, says Holmes Ward. But, from the start, WCVB decided to favor small to midsize charities, because most larger charities have in-house help raising money and supplies. "This Internet format," she says, "levels the playing field."

And the needs and opportunities abound. Items donated range from knitting yarn to homegrown eggs—20 dozen eggs a week by a couple (with 60 chickens, that is).

Holmes Ward loves the diversity. "One man's trash is another man's treasure," she says. "You never know what people are looking for until you put it up on the Internet."