How are these "employer's" finding my e-mail address?

Question

I am a fairly new yahoo e-mail user. It seems like every other day I'm receiving an offer from someone outside of the U.S. Some of the offers are from woman claiming that their husband died and left them a HUGE amount of money, and that they need my info to help them cash in some kind of beneficiary policy (this seems odd). Some are from "doctor's" stationed in England,Holland and even Africa...I'll give you guys an example:

Hi my name is Mike Wood

Your probably wondering why I'm contacting you. Well about a year ago my wife passed away, and left me 9.5 million dollars in a swiss account. I'm trying to get the money transferred over blah blah blah.

Or Hi I'm Dr Such n Such I'm looking for an admin assistant with reliable transportation who can cash my clients that I work with in the U.S. checks for me. Please send the following if you're interested in the position:

Full Name

Full Address

Phone Number

Where You Currently Work

Bank Information

Who are these people? & Why me?

Answer 1

Scams and spam. You've entered a contest or visited a questionable site. They've sold your address many, many, many times and the junk mail will keep coming. DO NOT reply to it and DON'T even open any questionable mail. Just move it to your trash bin and delete it.

Answer 2

just a scam that they use a robot to send to people randomly.

Answer 3

The are scam artists phishing for people to bit on one of their scams.  Once a duped user provides their info, they clean out your bank account.  They may buy e-mail addresses or just use programs to try different combinations and send spam to everyone possible.  Regardless, ignore and delete these e-mails.

Answer 4

It is a SCAM!

Originally from Nigeria; now it migrates everywhere.

Victims lost life, or money from this scam.

btw, Y! email is not clever enough, not able to filter out bad mails.

suggesting you to use Gmail.

contact me if you need an invite.

As to how they got your email address; with key strokes, they can get plenty of what they need to target a potential victim.