Unraveling Brothers" Online Lives, Link by Link It is America's first fully interactive national tragedy of the social media age. The Boston Marathon bombings quickly turned into an Internet mystery that sent a horde of amateur sleuths surging onto the Web in a search for clues to the suspects" identity. And once the search focused on Tamerlan and Dzhokhar Tsarnaev, the brothers" social media postings provided a rich vein of material to mine and sift. There are more than a thousand messages on Dzhokhar's Twitter account in addition to a profile page on VKontakte, a popular Russian social networking site, and in Tamerlan's case, a list of favorite videos on YouTube and what appears to be an Amazon wish list belonging to him (Amazon would not confirm whose list it was, citing its privacy policy.) These posts instantly became dots that people began trying to connect. Some details ratified the views of those former friends and neighbors who said they were utterly shocked at the brothers" possible involvement in such a horrifying crime. Other posts pointed to Tamerlan Tsarnaev's growing interest in Islamic radicalism and possibly a dark subtext to the friendly, boy-next-door affect of Dzhokhar. At the same time, they were reminders of the complexities of online identity - of the ways in which people strike poses and don masks on the Web (which can sometimes turn into self-fulfilling prophecies), and the ways in which the Web can magnify or accelerate users" interests and preoccupations. The younger brother, Dzhokhar, in particular, seemed utterly immersed in American pop culture, and concerned with the sorts of things that preoccupy many young men - girls ("miss u.s.a. is so sexy") and good times ("I am the best beer pong player in Cambridge. I am the #truth"). In fact, much of his Twitter feed is distinctive only in its ordinariness - ordinariness that stands in such startling contrast to the horror of what happened last week in Boston. There are lots of references to musicians like Chris Brown, Jay-Z and Michael Jackson; television shows like "Breaking Bad" and "Game of Thrones," and movies like "Spider-Man" and "Finding Nemo." He prattles away about Nutella and Frosted Flakes, complains about typos and losing his remote. "Pop-up adds are the worst, on par with mosquitoes," he tweets on June 17, 2012. Given the layers of irony, sarcasm and joking often employed on Twitter, it can be difficult to parse the messages of a stranger. Yet some of them can seem menacing or portentous, given what we now suspect: "a decade in america already, I want out," "Never underestimate the rebel with a cause" or "No one is really violent until they're with the homies." But others suggest a more Holden Caulfield-like adolescent alienation: "some people are just misunderstood by the world thus the increase of suicide rates." Sometimes, Dzhokhar sounds downright sentimental (unless, of course, he is being ironic): "There are enough worms for all the birds stop killing each other for "em." Parts of Dzhokhar's VKontakte page are harsher and more serious. Under personal priority, it says "Career and money." Under worldview, it says "Islam." There is a link to a video indicating outrage at the violence in Syria, and a link to an Islamic Web site that says "And do good, for Allah loves those who do good." Another video features a blind boy talking to an older man, saying he believes his blindness will be absolved on Judgment Day; the man starts to cry, and wonders how many people who have their sight are as committed to the study of the Koran as the boy. Other posts on Dzhokhar's page have a more sardonic edge. There is a link to a self-described "journal of sarcasm" called "Evil Corporation" (featuring a logo reminiscent of Angry Birds) and also a joke that goes like this: "A car goes by with a Chechen, a Dagestani and an Ingush inside. Question: Who is driving? Answer: The police. The videos linked to on Tamerlan's YouTube page - created in August 2012, shortly after a trip to Russia - are far more militant, and hint at a growing radicalization. About seven months ago, he posted a couple of videos of Timur Mucuraev, whom The Washington Post has called "the bard of Chechen separatism." Five months ago, he posted a video (subsequently deleted) under the subheading "Terrorists." The video, CNN has reported, featured a militant named Abu Dujana (a k a Gadzhimurad Dolgatov), who was killed by Russian security services. The video reportedly shows the leader in sunglasses, flanked by two others, their faces hidden by balaclavas, brandishing automatic weapons. Four months ago, a link went up on Tamerlan's YouTube page to a video called "The Emergence of Prophecy: The Black Flags from Khorasan." The black flags refer to a kind of Armageddon-like prophecy reportedly embraced by Al Qaeda - about jihadis rising up from Central Asia to defeat the infidels. A video link featuring the radical Islamic preacher Feiz Muhammad has been removed in the past several days; it included a denunciation of the Harry Potter books and movies as glorifying "paganism and evil" and teaching "children the drinking of unicorn blood and magic."