I am in the habit of making up email addresses on the fly when I register for things. Looking in my spam folder, in the last couple of days I've had spam to the

I am in the habit of making up email addresses on the fly when I register for things. Looking in my spam folder, in the last couple of days I've had spam to the email addresses I submitted to Adobe, Groupon and Abbey National Bank (now Santander). As people have pointed out email addresses are not secret, but if they've leaked out of these businesses' databases it's a bit worrying what else they might be leaking.