Relatives and friends helped them, yet because of the short notice many others could not travel to Minneapolis, where they were married last December in the art gallery where they had met. Ms. McInerny, 29, a social-media strategist for an advertising agency, and Mr. Purmort, 32, an interactive designer, then decided to live-stream the ceremony.
Virtual guests received an e-mail invitation a week before. It contained a link to purminerny.com, which directed them to go to the Web site at 4 p.m. for the webcast on Ustream, a live interactive broadcast platform in San Francisco. The couple also created a Twitter hashtag (#purminerny) that led 238 viewers to the wedding webcast instead of the 30 or so they had expected.
“The fact that guests were attending by the Internet and computer screen didn’t make it any less touching to us,” the bride said.
While some couples consider live-streaming alternatives for more-basic reasons (there are almost always relatives and friends who cannot attend the ceremony), other social-media-savvy couples want to beam their weddings to the digital universe in hopes that they will go viral.
Popular culture has begun to take notice. In this season’s finale of the ABC comedy “Happy Endings,” the character played by the actress Casey Wilson went to a wedding and turned out to be the only physical guest at a table with six laptops showing the faces of virtual guests.
“Right now, online wedding streaming is a novelty,” said Kim Forrest, an editor at WeddingWire, who watched the episode. “It’s indicative of something bigger. In actuality, it’s something that’s a great idea for couples who want to include more and more people in the wedding.”
Brian Beitler, an executive vice president and the chief marketing officer of the David’s Bridal chain, attributes the growing numbers of those who want to put on a show, for loved ones as well as total strangers, to the proliferation of wedding-dance videos on YouTube and an increasing tolerance for an open digital presence.
“Live-streaming weddings are just a result of the general trends in this digital era, where all things are becoming increasingly social and viral,” Mr. Beitler said. “People are just more open to sharing important events in their life.”
Although couples have the option of a password-encrypted Web site to limit who watches them marry, Brad Hunstable, the chief executive and a founder of Ustream, says that most of his clients are going public.
Max Haot, a founder and the chief executive of Livestream in New York, and his fiancée,Rachel Sterne, the chief digital officer of New York City, prefer to keep the live-streaming private for their wedding next month in East Hampton, N.Y.
“The reason we’re doing it is not because I’m the C.E.O. of Livestream,” Mr. Haot said. “It’s not about broadcasting it to the masses. We thought it was an amazing way to include people that want to be there but can’t be there and feel the moment in real time.”
Harmony Walton, a wedding planner in West Hollywood, Calif., said that live-streaming could complement a destination, which usually costs far more for guests to attend. According to the Cruise Lines International Association, a trade organization, there has been an upswing over the last four years in the number of couples transmitting real-time wedding webcasts from ships.
Other live-stream services include I Do Stream and Marry Me Live, which provide a network of videographers for live-streaming, as well as the platform technology for videographers and do-it-yourself couples.
According to Philip Ly, who is from Tolland, Conn., and runs an online service for couples looking for live-stream videographers, the cost depends on the location of the wedding but ranges from about $600 to $1,500, while the do-it-yourself package costs about $200.
Some couples start the live-streaming long before they recite their vows; now webcams are watching even during the planning. The proliferation of smartphones, iPads and other mobile technology enables brides to share their experiences in, say, shopping for a gown. To capitalize on this market, David’s Bridal said it planned to have Wi-Fi access in its stores later this year.
India Nicholas, a cousin of Ms. McInerny, was unable to attend the McInerny-Purmort wedding on such short notice, so she watched the live-stream and Twitter feed with her boyfriend at their Brooklyn apartment.
“When you’re sitting there in a church, you’re quiet for the hour,” Ms. Nicholas said. “When you’re able to live-tweet, you can say whatever you want. You’re right there with them and can share your thoughts with them. It feels like you’re part of that event though you’re miles away.”
(Since the wedding, Mr. Purmort has completed a round of radiation treatments, and is undergoing chemotherapy.)
While 130 guests physically attended Neil Inala and Tania Mandzy’s wedding in San Jose, Calif., on April 28, 50 more tuned in to the live-stream.
Mr. Inala, 37, a product manager at Google, and Ms. Mandzy, 35, a mezzo-soprano, broadcast a Ukrainian Catholic ceremony and a Hindu ceremony later in the day.
The couple sent an e-mail to their virtual guests five days before the wedding with detailed instructions and time zones to tune in to their broadcast, which required a high-speed connection and a Google Plus account.
All the guests added the bridegroom’s brother Andy Inala, who operated the live-stream at the wedding, to one of their Google Plus circles to view the video feed.
“I was looking at the Hangouts on Air technology and thought that it would be great for the people far away to watch the stream over the Internet,” Neil Inala said, referring to a Google Plus feature. “It’s kind of a destination wedding for everyone else because they live in different places across the country and internationally.”