SS BAKSHI remembers the first email he ever wrote: ‘‘It took me 20 minutes. I received a reply 10 minutes after I sent it to my son. And I thought, God, I can’t write another one.’’ It might be a slight exertion, but it’s one that many retired couples are willing to make. With children and grandchildren living abroad, an increasing number are hitching their affections to the Internet. The email has become the new bridge that fills the gaps between phone calls and annual visits. Now more familiar with the keyboard, 71-year-old Bakshi, a retired businessman who now lives in Gurgaon with wife Jasmer, 62, says they feel a tinge of disappointment if there’s nothing new in the inbox every morning. Their oldest son works in Sri Lanka and the younger one, who only recently returned from Russia, is about to move again. ‘‘Once my grandson, who was just eight months then, banged on the keyboard, and my son sent the result to me. He said this is his first message to you,’’ remembers Bakshi. That gibberish is now part of their online folklore, carefully preserved among other precious memories.