Erika Goyzueta recently searched, toured and purchased a two-bedroom cottage—all via her iPhone.

Ms. Goyzueta and her husband Jason Velez of Irvington, N.Y., had been searching for a vacation home on Cape Cod for four months. When their real-estate agent, Maureen Green, found a cottage listed for $199,000 in November, Ms. Goyzueta didn't want to wait to see the property in person. Instead, she took a video tour led by Ms. Green the next day.

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