E-mail traffic doubled in Europe on Thursday after four bombs exploded in central London. A snapshot of e-mail activity from security company MessageLabs found the number of customer e-mails it monitored grew from the average of 500,000 to 1 million an hour after terrorist attacks began. "Sometime after 9:00 a.m. BST (1 a.m. PDT) we saw e-mail traffic rise," said Alex Shipp, senior antivirus technologist for MessageLabs. "That's ignoring spam--that's half a million legitimate e-mails an hour up to 1 million. "We don't know what the traffic is, but we're guessing that it's 'Are you OK?' and 'Have you seen...