There are communities within the South Shore, virtual worlds that intersect with the real world when people of similar interests connect. The Internet is changing social dynamics, networks and more in the area, transforming how people interact.

Melanie Feehan grew up in Plymouth’s good old days, when neighbors chatted over fences while their children played together.

But when the 37-year old mother of four moved back to her home town this year, she had trouble meeting people. Frustrated, she joined a growing number of South Shore residents who are connecting with local people with similar interests online.

“I was reluctant to do it,” said Feehan. “I’m not into meeting people on the Internet.”

Feehan said the site meetup.com, an online social networking portal that facilitates group meetings, helped her strike up relationships with like-minded women of her age. Nearly 30 women have attended two “meet-ups” Feehan organized through the Plymouth Girls Night Out 30ish and 40ish Meetup since she created it in July.

“It’s like I’m a cruise director, and I get to plan fun events,” she said.

 Like Feehan, many South Shore residents are finding that using the Internet is an easy way to make social and professional acquaintances.

 For some, these connections play the same role that neighbors once did. Every day for two weeks after she gave birth to her now 7-week-old son, Kristen Brown received home-cooked meals prepared by friends - all of whom she’d met through the Internet.

 Brown, 30, who runs a business from her Marshfield home, has weekly playgroups and monthly mom’s nights out, all of which she said wouldn’t be possible without the connections she’s made online.

 “I didn’t have another avenue to meet people,” Brown said.

 Sociologist Robert Putnam’s mid-1990s book on the collapse of American communities, Bowling Alone, began years of academic hand-wringing over the disappearance of neighborhood friendships and strong communities.

 But new technology can help communities reverse that trend - and increase social ties - said Keith Hampton, a professor of communications at the University of Pennsylvania.

 The Internet is most likely to benefit individuals and the community when it combines the ease of online communication with face-to-face interaction, said Thomas Sander, the executive director of a civic engagement initiative at Harvard University’s Kennedy School of Government.

 Such Internet informality played a role for Maureen Irons, 55, of Braintree, who backed out of three in-person meetup events before she got the courage to go.

 “The options were sitting at home watching TV or being out with human beings, so it became a no-brainer,” said Irons. Now Irons regularly attends South Shore Dining Out meetup events and is a huge fan, she said.

 Angela Nuss, a 29-year-old Braintree resident who is that group’s organizer, also organizes a South Shore fitness group. “Online is like the way to meet people,” said Nuss. “It’s easier. It’s convenient.”

 Some people, like Ruben Austria of Quincy, first tapped online social networking sites to make business contacts. In July, he used meetup.com to organize a business event in Quincy attended by 75 people, who were previously strangers.

 In the process, he found like-minded individuals who are interested in business development, he said.

 “Meetup is a good tool,” he said, “a good example of using technology to bring people together.”

 But academics worry that local social ties formed over the Internet tend to be between people that are more the same than different, thus not as effective in uniting the greater community.

 “One could be concerned that our networks are becoming more homogeneous,” said Hampton, the University of Pennsylvania professor. “We only keep in touch with people who share our views.”

 Melissa Fox, a 29-year-old Holbrook mother, thought the Internet would allow her to meet parents more like her and her husband.

 “We were looking for down-to-earth people who were open-minded about parenting,” she said.

 Now, Fox organizes the South Shore Active Moms and Dads group for local parents.

 She said members of the group are great resources.

 In a similar vein, at a recent Dedham Mother’s Group meeting at a Dedham park, Theresa Strang, 32, chatted with organizer Katherine Sherrod, 29, as she prepared to leave with her 18-month old son.

 “He’s having a problem transitioning from two to one naps,” she said. “I’ll have to talk to you about that next time.”

 “We can always chat over email,” Sherrod replied.

Clara Long of The Patriot Ledger (Quincy, Mass.) may be reached at clong@ledger.com.