LOS ANGELES (AP) – When you sign up for Facebook or Twitter, you expect to get a stream of random messages from the people that make up your virtual social network – but pitches on homes for sale?

Real estate agents and others are trolling for clients on these and other popular online social networking sites, mixing home huckstering with their online networking. But is this a good way to sell a home or are agents’ sales pitches getting lost in the post?

Agents who use the social networking sites to market properties say they hope to generate referrals – just as you might tip off a friend about a new for-sale sign on a lawn.

“Tweeting is the same way,” says Duane Hopper, an owner and broker at Century 21 Real Estate Center in Seattle, referring to the term for posting messages on the microblogging Web site Twitter.com.

“There is a multiplier effect that can take place, particularly on very hot information,” adds Hopper, who posts information about homes he’s trying to sell and promotes himself on Twitter, Facebook, LinkedIn and ActiveRain.

Twitter lets users create profiles where they can post messages of up to 140 characters that can be viewed by anyone with Internet access on a PC or mobile phone.

Hopper started using the site last fall. Since then, he’s racked up more than 600 people who have elected to “follow” his tweets. (By comparison, celebrities such as Britney Spears have hundreds of thousands of dedicated tweet recipients.)

A recent look at Hopper’s Twitter page revealed more than 20 tweets, although not all the posts were real estate-related.

Hopper liberally mixes tweets about the Mariners baseball team – “Getting excited for Home Opening Day for the 5-2 Mariners” – with posts on his daily real estate rounds: “On my way to paint For Sale Post at our hot new Kirkland listing. Can’t anyone get the color right?”

But often, Hopper’s tweets are listings of homes for sale that read like word-stingy newspaper classified ads: “At Juanita Multi-level photo shoot,” started a recent post. “Listing coming. Hurry if you have buyers. Under $500K, 2,190 feet. 3Bed 2.5Bth.”

Hopper also sometimes includes Web links to a virtual tour of the home.

Jo-Ann Cervin, a buyer’s agent with ZipRealty in Las Vegas, began using the site just last week under the handle “LV-Cheap-Houses,” but she’s wasted little time posting a barrage of bulletins urging readers to buy now.

So far, she’s got 44 users subscribing to her tweets, which mostly consist of homes for sale or calls to action like this one: “Las Vegas bank owned properties are seeing multiple offers! The great deals are going QUICK!”

Cervin isn’t worried that the barrage of home listings via tweets will scare off those who subscribe to her missives.

“They’re choosing to connect with me,” Cervin says. “I’m not spamming.”

On Facebook, which boasts more than 200 million active users, many real estate firms have profile pages that sometimes feature home listings and discussions about real estate. Some agents set up commercial Facebook pages, which are open to all users.

Many agents use one of several Facebook applications designed to highlight home listings on their profile page, such as eListIt’s My Listings widget. Others let users pipe in video tours.

John Ammirati, an associate broker with Century 21 Prevete in Long Insland, N.Y., created a Facebook page for his company where his agents log in and post listings and information about open houses.

“We’re just starting to get into video,” he says.

Hopper takes a more subtle approach on Facebook, however.

He tries to keep it personal, posting photos of a recent vacation, for example, while only sprinkling in real estate listings and links to virtual home tours.

“I don’t want to overwhelm people,” Hopper says. “It’s like getting unsolicited advertising if you overdo it.”

Cervin also only recently began playing up her real estate business on Facebook. She hopes her friends will refer her to would-be homebuyers. She’s also on ActiveRain, where she blogs about real estate and, ultimately, hopes to nab some client referrals from other agents on the site.

Still, Cervin says she hasn’t received any business directly from her social networking activities – yet.