It used to be axiomatic that a rise in temporary employment was a sign of economic recovery and that permanent hiring would not be far behind. In recent months, temporary hiring is on the rise, but the old pattern does not seem to be holding. More temps are being hired and they're being kept longer, but fewer employers are making them permanent. So there's flexibility for the employers, but instability for the employees. Temps are now being hired for high-skilled professions -- from engineering to finance to information technology — even at the executive level. Will temporary work be a permanent feature of the new economy? Will some workers choose nomadic careers while others struggle to fend for themselves?