The  A California startup is extending social media to the dead.

I-Postmortem Ltd., based in Palo Alto, allows clients — while still alive — to create an interactive memorial to themselves through photos, letters, poems, and audio and video files.

After death, a client can also send timed messages — to a son on his 21st birthday, say, or a daughter on her wedding day.

“Imagine if we had a service like this in the 1920s or 1930s,” company founder Jacques Mechelany said by phone Tuesday of the legacy side to the technology.

We would be able to see what people were saying about their own life, their choices, the problems they confronted,” he said. “We would have a wealth of information.”