Hier ist eine schöne Erklärung: "#icanhazpdf is a Twitter hashtag used to coordinate the exchange of scholarly papers. Suppose that Alice needs a certain journal article for her research, but neither Alice nor her employer have a subscription to the journal which contains it. (Alice could be a research scientist at a small nonprofit organization, or even a cancer patient trying to educate herself about her disease.) The article is not Open Access, nor is it available in an institutional repository, nor does a version exist on PubMed Central or the arXiv. Alice posts a link to the paper on her Twitter account, marking it with the "hashtag" #icanhazpdf. Anyone who notices checks to see if they have access, such as via their university's institutional subscriptions, and if they do, they download the article and send it to Alice. In February 2012, it is becoming standard practice to delete the request tweet after the request has been fulfilled" (Quelle: Eureka Journal Watch, CC-BY)
Eine ähnliche Sache gibt es auch auf Reddit: "This reddit is for requesting and sharing articles available in various databases, as well as discussion relating to the material".
#icanhazpdf etiquette may prevent me from naming the tweeps who sent me the Science pdf I needed, but it can’t stop me from thanking them.— Karen James (@kejames) April 10, 2013