An interesting effect of the changing business landscape has been a change in the attitude toward departed employees. In the past, many companies treated those who'd left (whether voluntarily or involuntarily) as pariahs, traitors, or losers. Today, they're generally considered a pool of potentially desirable rehires. After all, if you leave Company A for a job at Company B, you will still retain useful knowledge of how Company A operates. In addition, you will also develop valuable new insights into the strengths and weaknesses of a competing firm. Thus Company A will probably be happy to consider hiring you back. Rather than a "traitor," you're more likely to be called "a returning alumnus."