Google claims to give you ads they think will give you the highest revenue based on your content of course. Though like I said earlier you can influence the choice of ads you get on your page both in terms of color and price.
Signing up for google is quite easy whether you are a site owner or you own a blog. If you have a blog (you need a gmail account) providing you are using blogger.com, from your dashboard choose monetize and click on the Adsense tab. Just follow the steps to register below and you are on your way to Start earning money
The first step will be to choose the type of account you want; Individual (cheque will be written in your name) or company (check will be written in your company name). You also choose how you want to receive your check; through EFT (Electronic Fund Transfer) Local currency Cheque or Secured mail . I recommend getting your mail by mail. It’s better to get your mail by direct deposit especially if you are in the U.S, for those outside the state you could use any other means. If you decide to use secured mail, bear in mind that you will bear the cost.
Next step, enter your site URL. If you are signing up through your blog, your blog name appears here (don’t even think of entering two URL) you can only use one at least during signing up.
Choose the type of ads you want you want and then sign up. Google then ask you to wait for 48 hours for your registration (though in my own blog was just five minutes.