The online world can be dangerous, you are quite correct. You will not believe how many people still fall for this (if they didn't, they wouldn't still be sending these mails, now would they. I can well believe that more than 80% of all emails sent are for spamming purposes, as I have to go through some of them to see if legitimate ones were caught by the the spambucket.
People should take a little more care with their details and also should not click on every link. If it sounds too good to be true, it probably is.