Is Obama’s Blackberry Secure?

1. i sent an email to a friend with a single obscure-ish word ("pearly") in the subject line. later that day, i received a spam message with the subject line "re: pearly").

2. a few weeks later, i sent out an email about a new volkswagen i bought (sent it to a different friend). i started receiving spam that mentioned volkswagen cars in the subject lines a few days later.

i was sending email out via smtp and not through an exchange server and there are, of course, a lot of people in the smtp chain who could be responsible, but it never happened when i sent email from my notebook nor has it happened since i got rid of my blackberry.

it could be coincidence, of course.