People who start a site specifically to try AdSense (although you're not meant to) usually start with a free blog host. Blogger is popular because it is very easy to implement AdSense on it.
people usually start with any website possible. However I recommond, building a quality site with quality content and traffic. once you have a good flow going, then throw the ads up... just my .02
A lot of ppl start to earn money using blogger.com and services like this. i prefer to start with a ltd and paid webspace ( Uptime guarantee and better support, mostly! ). You can get Domain + great Webspace(php,mysql..) for about 10$/month, that's not too much!
It depends. I started with affiliate sales and I still do much more from affiliate sales from AdSense, but I realize that AdSense potential is something that can't be ignored.
I started with adsense since i am blogging.. for more than 2 months now.. not making much.. but its a start
o.k. one more question? some ppl have told me that i need to wait to have enough traffic, otherwise i'll drive ppl away? is that true?
If you put more ads then content, yes you'll drive people away. Most people are now aware of AdSense and recognise it as an attempt to make money. As long as it is well blended and doesn't detract from the content it shouldn't be a problem.