Last year a few students asked for my endorsement on LinkedIn. I wrote a few, growing more uncomfortable with each about their lack of a specific audience and permanence online. I decided last fall not to endorse anyone else on LinkedIn or comparable sites. I didn’t have to apply my decision until yesterday, when I rejected a former student’s request for a LinkedIn endorsement. I explained that I would be happy to recommend him to a specific employer or graduate school; he was a terrific student. My rejection has nothing to do with his merits. I am rejecting the concept of permanent, open-ended, recommendations.