In summary, altmetrics can reveal when a paper published many years ago is used in new contexts. Because of new communication and education efforts by scholars who use social media, foundational works like this 1990 paper are occasionally brought into the conversation as evidence or illustration during a discussion. This usage adds to an understanding of the lifecycle of a scholarly work, in that its continued use after publication relies not just on other scholars who cite it, but also those who are engaging in public discussions on important topics using foundational works of scholarship. 

Posthumous Social Media Attention

When Dr. Starzl passed away on March 4, 2017, many news outlets covered his passing and described his body of work in order to contextualize his contributions to medicine and science. In addition, many of Dr. Starzl's students and colleagues shared their history with Dr. Starzl, and many of them linked to their favorite papers. 
The most discussed paper in this context was perhaps Dr. Starzl's most monumental contribution, a 1968 article on the first successful series of liver transplants entitled "Orthotopic homotransplantation of the human liver" \cite{4877589}. The journal Annals of Surgery, which published the paper in 1968, shared the digitized version of the paper on Twitter to honor Dr. Starzl's passing. This tweet was then retweeted 249 times as of the writing of this paper, and many Twitter users replied and shared their own experience with the paper or Dr. Starzl himself, commenting on his impact on their careers and the advancement of the field that happened because of this particular work.