Speaking of spam, why did you feel it necessary to post your question twice?
If you would check the threads you may note that people with helpful responses appear in most of the threads and you don't need to yell to get their attention.
As for you questions:
Why you? Your just lucky I guess or it could have to do with where you go on the web. Those who visit the red light district run a higher risk of STDs. Spammers are clever scum. They collect your name/address when you visit their sites. They may have been lucky the first time but after that you were a known target and every time you read one of their emails you reinforced their targeting. To slow down their attack you should use a firewall to block outgoing information you don't want to send and configure your mail reader to NOT display remote images. Why? because in the HTML of some of these slutty emils are bits of code that send your email address out when you open the email

. This is a flag to the spewwer that your address is a "good" one and you get even more spam. If you don't display remote images and use you firewall you can stop the outgoing information.
On the other hand you could just have bad luck. Dayly my domain gets email addressed to mailboxes that have never been used here. These random name atacks sometimes get lucky. You open the email and they have an aha! experence and add a new address to their list (ref firewall above).
Then there is things like spybot and Ad-Aware programs to help make sure your computer is not helping others without your knowlege.
Be of good cheer, this too will pass

.