Taglit-birthright Israel turned ten this year. From its start as the brainchild of a handful of American donors and Israeli politicians and the target of skepticism and scorn, it has grown into one of the largest and most admired educational projects in Jewish history. As Jewish affiliation threatens to shrink and weaken in the affluent countries of the West, birthright has set a goal of making Israel and its vast and very different Jewish civilization a normative experience for hundreds of thousands of Diaspora youth. This isn't your grandmother's Zionism. Birthright doesn't tell its participants to make aliya. It doesn't demand observance or urge lifestyle changes. It doesn't hold a view about God or the West Bank. Its methods are simpler, and so, it hopes, more effective: The encounter with a Jewishness that is rooted and collective, a nationality, serves as a demonstration for birthright participants that Jewish identity is more varied, complex and interesting than what they have experienced in the past. Already, 220,000 Jewish college-age youth have had this experience. Sensing that the encounter with a radically different Jewish community is as important for Israelis as for Diaspora Jews, birthright brought 40,000 Israelis, mainly soldiers and university students, to join the participants from the Diaspora for several days of their 10-day journey. For the first time, these Israelis saw their own country through the eyes of a wholly different kind of Jew. Birthright's success has been a surprise to many. A tourist-like trip to Israeli landmarks and museums was not expected to have the effect discovered in careful academic studies conducted at Brandeis University: Alums beginning to explore their identities and engage in their communities as never before. Perhaps this pessimistic expectation is the reason that Jewish organizations and foundations have been late to use birthright as the platform it could be. A shared experience of 220,000 of the less-affiliated among Jewish youth could be the springboard for organizational involvement, educational networks, Shabbat dinners. Only in the past couple years have initial efforts in this direction begun, through Hillel, Birthright NEXT and collaboration with Masa. But these programs don't reach the majority of alums. Most remember their "bus friends" - in this day and age, they connected on Facebook while still on the bus. They even remember fondly the soldiers who accompanied their trip and struggled to explain to their foreigner-brethren the meaning of Israeliness. But these connections are wasted if they are not directed at new Jewish experiences back home. The challenge birthright poses to the Jewish world is how to transform their success into something of an altogether different scale. When a quarter-million young Jews have visited Israel at the Jewish people's expense, it is a tragic waste that their Jewish communities make little effort to continue their engagement. Ten years, 260,000 Israeli and Diaspora participants, countless friendships, Jewish conversations and academic studies - and the question remains: Where's the follow-up?