You know them by their e-mail. It comes from places like hotmail.com or yahoo.com— free accounts that they can check from anywhere— or bargain providers like Panix. Even when they've got a steady gig, they won't use a corporate address because they won't be there long enough to care. At Microsoft, they're called "Adashes" because their @microsoft.com accounts are all marked with an "a-" before their name ("a" for temp "agency"). "It's so that when you send mail to anybody in the company, they know you're a contractor," says Mike Blain, an ex­Microsoft adasher. "Then they don't take... More >>>