9/11. It needs no year, no further explanation.

But the instant recognition and raw power of that phrase has made it easy for that terrible event to slide into pop culture. Eight years later, the World Trade Center is still a hole in the ground, but now surrounded by souvenir sellers with 9/11 T-shirts and knick-knacks.

One problem with rebuilding on the site is that, in these times of recession, there isn't enough commercial demand for the new buildings that would replace the World Trade towers. Spending billions to say "You can't beat us" to terrorists seems foolish to many if the buildings will sit empty.

There is more agreement on other legacies of 9/11. Much of the goodwill reflected in candelight vigils from London to Jakarta to Teheran （yes, thousands of Iranians took to the streets to mourn that loss of life in the US）. has been lost in the intervening years, and the US is working overtime to reconnect with a global community that has much to fear from more terrorism. The US has often lost the information war, too: Many otherwise sensible people around the world believe "The Jews" were behind the attacks, that the Pentagon was hit by a bomb not a plane, and other nonsense.

But the energy and national purpose that washed over the US on September 12 has ebbed at home as the threat begins to feel remote there, too. So it's exciting to see today's anniversary take shape as a national day of service.

"Eight years ago, the tragic events of that Tuesday morning inspired Americans to come together in a remarkable spirit of unity and compassion," said President Barack Obama this week. Many have been quick to blame his predecessor for the evaporation of that spirit, but many in the US will put memory and muscle into community service efforts today: disaster preparedness, neighborhood cleanups, "care packages" for US military in war zones, and other projects.

The effort began on the first 9/11 anniversary in 2002, but has not taken room in all 50 states until this year.

It's an effort that brings out the best in Americans.

9/11.无须指明年份，也不需要进一步解释。

但一眼就能知道，而且原始力量使它这个可怕事件轻而易举地就进入了大众文化。八年之后，世贸中心仍然只是地上一个洞，但现在则被卖9/11T恤和小玩意的纪念品小贩所包围。

在此地重建的一个问题是，在当前的衰退时期，对重建世贸中心的商业需求不足。花上数十亿美元来向恐怖分子表示"你打不倒我"在许多人看来似乎有点愚蠢，如果建筑仍是空置的话。

而对9/11的遗产则存在更多一致。从伦敦至雅加达至德黑兰的烛光守夜（是的，成千上万的伊朗人走上街头哀悼那些美国失去的生命）中反映出来的善意已遗失在这些年间，而美国也在加倍努力与全球共同体重建联系，这个全球共同体还有很多东西需要操心，而不仅是恐怖主义。美国也常常在信息方面打败仗。世界上许多敏感的人认为"犹太人"才是"9.11袭击"的募后指使者，他们认为五角大楼是被炸弹炸掉的，而不是飞机。当然还有其它的胡扯。

但9月12日席卷美国的能量与国家意志已在国内渐渐退潮，因为威胁开始渐渐觉得远离。因此，看到今天的周年纪念日作为全国服务日很是有点激动。

"8年前，那个周二早上的悲剧事件鼓舞美国人以一种空前的团结与同情精神聚在一起",本周奥巴马总统这样说。许多人很快责怪他的前任让那种精神蒸发了，但美国许多人将化记忆与力量为社区服务努力：灾难准备、社区净化、到战区为美国军队的"爱心包裹"和其它活动。

这种努力在2002年第一年9/11周年纪念日就开始了，但直到今年都还没有在所有50个州占据太据地位。

这是美国人所能发挥最好的努力。