The San Diego Union-Tribune and the upstart San Diego News Network are launching competing “Daily Deal” products, with Facebook and Twitter accompaniments, and will try to eat into the lead in the local market that has been assumed by Groupon (and Living Social and many others).

The SDUT launches its Groupon-like “Sign On San Diego Daily Deal” tonight at midnight with a special offer to get $50 worth of grub at Acqua Al 2, a chic Italian eatery, for $25 (and actually, just $15 if customers use their $10 deal bucks for signing up or referring a friend). Under rules of the promotion, 50 people need to sign up for it within a 24-hour period. Six people signed up for the deal within the first hour.

The SDUT’s Daily Deal sits on a platform provided by Click-N-Shout, a Cleveland-based company — one of apparently 155 rivals, per Groupon — that is testing the waters for newspapers with the SDUT. The newspaper’s sales forces have been offering the Daily Deal as part of their portfolio for a few weeks, and there is roughly a month’s worth of inventory in the system now.

Site GM Mike Hodges notes that The Daily Deal is hardly entering virgin territory. Roughly 80 percent of potential advertisers have been approached by Groupon or other Deal-a-Day services. But the newspaper believes it has many advantages over the competition, including the ability to promote The Daily Deal on the right-hand corner of the cover of every print issue and a database of 90,000 “special offer” e-mail subscribers.

Hodges believes The Daily Deal will prove complementary to other special e-mail offers that have long been provided by the newspaper, and notes that it is possible that many users will get a daily deal and special offer in the same day. Newspaper advertisers are being approached first.

Meanwhile, The San Diego News Network, the flagship of the fledgling U.S. Local News Network hyperlocal network chain, is launching its own, similarly titled “Daily Deal” next Monday, April 12. Built to custom specs by Deal Current, a local San Diego software company run by Jimmy Hendricks, the site has sold out its first month of inventory with local companies such as Hairspray salon, Vagabond Kitchen, Extreme Pizza, The Comedy Store, Cookies by Design, Cupcake Love and All American Grill.

Company President Chris Jennewein says he believes that “very competitive” pricing — presumably more favorable than the 35 percent to 50 percent of coupon value assessed by Groupon — will make a difference. It is also important “to have a sales executive from a local company that you can trust rather than a telemarketer,” he says.