David Letterman is sorry for the mean things he’s said about Jay Leno, and he declared a truce on last night’s show. While crafting a Twitter message to the other late night hosts, Letterman said, “I’m burying the hatchet. I like all of these guys … So now I’m calling for an end to this, because we’ve all become brothers.†I guess he’s hoping Jay can explain to him how Twitter works, because Letterman’s tweets all begin with “Hash Tag:†and don’t include any @ tags. Aw, watching David Letterman use Twitter is like watching your grandpa try to …use Twitter, I guess.