Virtually everyone who has used e-mail knows the feeling: You press the send button and realize that you just sent something embarrassing to someone by mistake. That happened to Cornell University on Wednesday: It sent welcoming letters to 1,700 high school students who had submitted early-decision applications, including nearly 550 who had already been rejected in December. “Greetings from Cornell, your future alma mater!” the e-mail letter began. “Congratulations on your acceptance into the class of 2007!” Within a couple of hours the university followed with an “oops” letter, admitting that it had made a mistake and offering its apology “for any confusion and distress this message has caused.” It said that the message was the result of a “systems coding error” and that it had fallen short of its goal of treating all applicants “with sensitivity and respect.” College admissions officials say that mistakes at admissions offices are not unusual; many of them process thousands of applications in a matter of weeks. What was unusual here was the scope. Full Story