WordPress.org

Do I need to get adcode from yahoo or google?

No, the plugin will automatically generate the ad code for you, you just need to put in your publisher id and optionally a channel id.

Do I need to insert any tags into my posts to make it work?

No, the plugin will automatically insert adsense or ypn ads into ALL your posts by default, there is nothing to be done manually, you only need to insert tags when you do not want ads to appear in a certain post or if you want to specify a certain point where the ad should not appear.

Does this plugin change my post content in the database?

No, this plugin inserts the ad code only after the content has been retrieved from the database by wordpress, your content is not changed. So you could just disable this plugin and all the in-post ads would be gone from your blog.

Why does my page only show white blocks but not ads?

First make sure you put only numbers in the adsense account number field, meaning there should be no ca-pub- or pub-, only numbers. If it still doesn't work, then make sure you have less than 3 google ads on your entire page or else google will automatically turn your ads into white block.