I have a friend who is using Thunderbird (I use it also) who recently received an email from a company who had broadcast to 212 customers using CC: instead of BCC:. Now, at different times when my friend receives an email from someone not even related to the company, it has all 212 customers showing in the CC: box. Does his computer have a virus? What causes that? Those 212 customers have nothing to do with the later emails he has received.

Any ideas?