I have a lot of small site with fewer visits (<50 visitors/day). So, Should I put ads on the site fewer visits ?
Go for it, if you build it they will come. As your website grows, the more ways to monitize the better.
your friends are obviously not your friends, its actually easy to get banned from sites made of shit, is your site made of shit?
I create game site. >10 sites. All site, I get game from mochimedia and they have duplicate game. Ex : site1.com/angry-birds, site2.com/angry-birds.
You can place ads even on sites that have few contents but make sure you stick to the AdSense TOS. If yur site has quality content that matters a lot. Like Ceekeigh said, pay attention to ads later...first thing first...prepare useful contents.
Makes no sense at all.You will not be banned for low traffic but insetaed for violation of Terms and Conditions
A website with less than 500 visitors per days makes only a few cents.So first increase your visitors and readers and afterwards use adsense