ON OCT. 18, 2009, Mac Tonnies updated his blog, sent out some public tweets and private messages via Twitter, went to bed and died of cardiac arrhythmia. While he had experienced some symptoms that indicated potential heart problems, his sudden death came as a shock even to those who knew him well. He was 34…

The last entry on Posthuman Blues was titled “Tritptych #15,” a set of three images with no text. The first comment to this post came from an anonymous reader, wondering why Tonnies had not updated the blog or tweeted for two days. Some similar comments followed, and then this: “Mac Tonnies passed away earlier in the week. Our condolences are with his family and friends in this time of grief.” The author of that comment was also anonymous. After a rapid back-and-forth about whether this startling news was true and some details of the circumstances, that post’s comment section transformed into a remarkable mix of tributes, grieving and commiseration. You can still read all this today, in a thread that runs to more than 250 comments…

The most remarkable set of connections to emerge from Tonnies’s digital afterlife isn’t among his online friends — it is between those friends and his parents, the previously computer-shunning Dana and Bob Tonnies. Dana, who told me that her husband now teases her about how much time she spends sending and answering e-mail (a good bit of it coming from her son’s online social circle), is presently going through Posthuman Blues, in order, from the beginning. “I still have a year to go,” she says. Reading it has been “amazing,” she continues — funny posts, personal posts, poetic posts, angry posts about the state of the world. I ask her if what she is reading seems like a different, or specifically narrow, version of her son. “Oh, no, it’s him,” she says. “I can hear him when I read it.”