"What do you have up your sleeve for your love tomorrow??? #getexcited#ValentinesDay," was the final message from Reeva Steenkamp, the model and girlfriend of South African Olympic star Oscar Pistorius, who was killed in a shooting in which her boyfriend is charged.
Michael McWatters, a technology professional, said he had been collecting these tweets with colleague Jamie Forrest, "not sure whether our project was something we really wanted to announce formally or not".
But he said the "grim tragedy" in South Africa prompted them to make the site public. "In many of the tweets there you'll likely find no deep meaning. In others, however, lie fascinating, inspiring, frightening, and perhaps tragic insights," he said.
Caleb Moore, a snowmobile racer who died of injuries suffered in a crash during the Winter X Games in Aspen, Colorado, said in his last twitter message, "Check out my fan page!" and provided a link to a Facebook site.
Aaron Swartz, the internet freedom activist who committed suicide as he faced criminal prosecution, also wrote an innocuous message in his final tweet.