How to avoid being banned by yahoo answer
 

Hi friends,
I post a comment with one link, and my account was banned.
How can i do it effectivly?
How to comment with link?

Probably the link you posted contained viruses/ malicious programs/ self promotion.
Other reasons could be ranting, usage of obscene content, wrong categorization, copy/ pasting, posting the same question over and over etc...

The chances of recovering a banned YA account are bleak. So, all you can now do is create a new one and be very careful as to how you contribute.