Michael Hodge is chief executive of FullCircle Social Networks, a start-up that allows smartphone users to find and interact with other people near them. (Jeffrey MacMillan/JEFFREY MACMILLAN)

FullCircle is announcing Monday that it has raised $3 million in venture capital and moved into a 5,000-square-foot office in Herndon, as the upstart looks to tackle the often-tricky business of social networking.

The firm has built a location-based social network for smartphone users to find and talk to people near them — whether that’s a person they know or a stranger with shared interests.

Though Facebook and Twitter have enjoyed explosive popularity, building new social networks can be difficult. Getting users to sign up for yet another service can require hefty marketing expenses and getting them to interact with the network regularly is often harder.

Chief executive Michael Hodge said FullCircle counts 500,000 users to date, including those that were added through a soon-to-be-announced business partnership.

“To the extent we can make it fun and entertaining and useful, we should be able to make the members grow,” Hodge said.

In that vein, FullCircle plans to unfurl three features in the coming months that Hodge said could keep users engaged with the app and open new revenue streams for the firm.

GeoCircle will alert mobile users when a particular individual comes within a designated distance. That can be a specific person, such as a good friend or relative, or someone more generic, such as a fellow Redskins fan.

Nearby SuperDeals shows a pop-up advertisement for discounted products in the user’s general area. Unlike daily deal purveyors Groupon and LivingSocial, Hodge said FullCircle will charge a small fee for each user who clicks on the ad, rather than take a cut of the sale.

Lastly, the company has a more ambitious feature under way called BCast that would allow users to livestream their surroundings to others. That feature has technical hurdles to overcome, Hodge said, and will likely be the last to market.

Apps like FullCircle must contend with what Hodge described as “the creepy factor” or users’ aversion to the idea of having their location tracked.

The company has installed a variety of privacy measures, such as the ability to block people or hide your location, and Hodge said the technology is bound to catch on as people rely on mobile devices for more activities.

“I don’t think you can overlook what is the tidal wave of geo-social usefulness that is coming down the pike.”

Cast your vote

Ten local entrepreneurs are vying for cash prizes in the StartRight business plan competition, an annual contest organized by Rockville Economic Development Inc.

This year’s crop of companies are peddling a wide array of products and services, many of them rooted in technology. Take a look at the 10 ventures below and cast your vote for the most promising one at www.capbiz.biz.

Unique Optique provides eye care services and artfully designed glasses.

Autonomy Engine uses software to monitor people’s tone of voice.

Tuko Pamoja sells crafts and other goods produced by women in Kenya.

SameGrain is a social network that connects people with similar interests.

Unbound Concepts offers software to analyze the reading level of educational texts.

Lifelong Technologies licensed a device to track the activity of patients with walkers, canes or crutches.

Camp Easy gives parents an online portal to find and register for camps.

The ColorCarton Group created a milk container that changes color as its contents begin to spoil.

Sensory Shield is developing a portable device for people with autism to create personal space and block sensory stimulation.

ICOW connects students in the United States and China, and facilitates study abroad trips.