The entrance to Google headquarters is seen in Moutain View, Calif., Tuesday, April 6, 2004. Google Inc. hails its free e-mail service as a welcome breakthrough in online communication, but consumer watchdogs are attacking it as a creepy invasion of privacy that threatens to set a troubling precedent. Although Google's 'Gmail' service isn't even available yet, critics already are pressuring the popular search engine maker to drop its plans to scan e-mail content electronically so it can distribute relevant ads alongside incoming messages.

词汇：

hail
 n. 冰雹, 致敬, 招呼, 一阵
 vt. 向...欢呼, 致敬, 招呼, 使象下雹样落下, 猛发
 vi. 招呼, 下雹
 int. 万岁, 欢迎

breakthrough 
 n. 突破

watchdog
 n.看门狗, 监察人(员), 监督人(员)
 adj.看门狗的, 充当监察人员的

creepy  
 adj.爬行的, 匍匐的, 皮肤上有足爬似的

precedent
 n.先例