Global technology firms are pitching in on earthquake rescue efforts in Nepal with services such as free calls to and from the country to functions that track survivors and relay the news to worried relatives and friends overseas.

Search giant Google Inc. on Saturday launched its Person Finder service, which allows users to post and search for information about missing friends and loved ones. The feature, which Google created in response to the destructive 2010 earthquake in Haiti, showed it was tracking about 6,300 records...