WordPress.org

How to enter several ads to a single text box?

Separate your ad blocks with <!--more--> sequence.

How many ads every instance of widget could handle?

Number of advertisements in each instance is unlimited.

Can I use Google AdSense code as one of my ads?

Of course, you can use any HTML you wish (AdSense, Clicksor, Chitika, and everything else).

WordPress shows `'getad()' function is undefined` error

See explanation on the Description page in Migrating from AdRotator plugin section.