As reality television has exploded, so has the demand for “real” contestants. At the same time, online social networks have grown into a major means for people to interact and connect.

These two growth curves have collided, giving birth to potent recruiting tools for reality shows. Casting directors can use the Web to supplement their traditional, labor-intensive efforts — throwing a wider net and possibly saving money.

“In the old days you would put the word out, and the next day you would get resumes, pictures, tapes, and decide who to bring in,” says veteran casting director Marki Costello (also owner of management company CMEG and granddaughter of Abbott & Costello comedy duo’s Lou Costello), who has provided contestants for shows ranging from Chuck Barris’ dating and newlywed games to ABC’s “The Bachelor.”

“Now we’ve got electronic submissions. You call Gotcast or go to Facebook or MySpace, you tweet about it and cast wide nets,” says Costello. The social sites help her find “people who aren’t jaded, don’t live in L.A., who are the real deal of being real.”

While mass-market networks like Facebook, MySpace and even Craigslist can be used to spread a casting call, specialized sites like Gotcast, RealityWanted, Talent6 and others are carving a niche for themselves by catering specifically to aspiring reality-show contestants — and bringing them to the attention of casting directors.

Gotcast was launched by entrepreneur Alec Shankman at the end of 2007 with venture-capital backing. Casting directors post their calls on the site at no cost; its 250,000 members upload their profiles — including resumes, images and videos — for free. But there’s a catch: If they wish to participate in multiple casting calls at the same time, they have to pay a subscription fee of $9 per month. “We charge them if they want to use it as an employment tool,” says Shankman.

One Gotcast user, E! Entertainment’s Annie Roberts, who has cast such shows as “The Soup,” “Daily 10” and “E! News,” says the site is “user-friendly for casting directors. It lets me get very specific about what I want, and the users submit themselves.”

Brandon Riegg, a development exec at ABC who oversees the network’s reality shows, including “Dancing With the Stars” and “Wife Swap,” has also used Gotcast for a special Super Bowl edition of “Wipeout.” “We were searching for couch-potato guys competing against female cheerleaders,” he says. “It worked well for us because we were looking for something very specific, which is not easy to do with more general casting calls.”

Robyn Kass, who has cast such shows as CBS’ “Big Brother” and TV Land’s “High School Reunion” through her shingle Kassting, has used sites like Gotcast and Reality Wanted, but sometimes prefers to scour the wider social networks for people who fit exact descriptions.

“Online we can search for, say, blond guys with seven brothers, or for people who fight with their parents,” says Kass. “We send them personalized messages to let them know about a project we’re working on.” While many recipients are suspicious at first, she says she’s had good luck with such cold-call emails.

Still, special-purpose casting sites continue to sprout. One of them, Taltopia, offers several levels of participation. The site’s basic, free membership “limits the amount of castings you can apply to,” says co-founder Anthony Zanontian. “If you want to apply to multiple casting calls every month you can upgrade your account.”

Three upgrade plans cost about $5, $10 and $15, respectively. “At each level you get a different amount of exposure and can do more things on the site,” says Zanontian. Taltopia offers members some interactive features, including “fame bucks” and a “fame and shame” game, both of which encourage members to grade one another, allowing the most popular to rise to the top — presumably making the search less tedious for casting directors.

Yet another approach is taken by MyStudio, which is building small, automated video recording studios where customers pay $20 to create a short high-def video of themselves performing anything of their choice, with or without their own musical instruments, or to music from several thousand EMI songs the company has licensed — against a moving green-screen background they pick from a menu, says MyStudio co-founder Larry Ryckman.

The resulting videos are burned onto a DVD on-site and also appear on a website and can be accessed only by the customer via a unique code, and can be forwarded to casting agents or embedded into other sites. MyStudio has locations in West Hollywood and Scottsdale, Ariz., and plans expansion into New York, Las Vegas and Nashville, Tenn.

A year ago MyStudio partnered with Mark Burnett Prods. on auditions for “Are You Smarter Than a Fifth Grader?” and today the company is working with Simon Fuller and Perez Hilton in their cast quest for “Boy Band,” a project still in development.

While electronic casting technology may be able to cut some costs, few independent casting directors want to talk about it. “I would never tell that to the producers,” says one.

But on the inhouse side, savings are a definite benefit. Casting sites “bring costs down because we don’t have to hire as many recruiters to go out and find people,” says E!’s Roberts.

ABC’s Riegg agrees that online and electronic casting are ways “to process a lot of people at once, and to get to areas that you just don’t have the manpower or the budget to reach.”

But no one believes that online casting will ever fully replace traditional methods. “I don’t think one precludes the other,” says Riegg. “Maybe on certain shows you can reach in one sweeping motion a lot of people you would otherwise have a hard time reaching. But there’s still value of having our talent people go see these folks in person.”

The online sites “are an avenue, but not the only avenue,” says Kass. “They’ll never replace flying to Dallas, walking into a store and finding that cute southern belle.”