I know that you can have only 3 ad units. I want to put a unit on each post in a blog. When search result shows say 7 posts, what will happen next ? They are filtered, so I cannot show more than three units, but is it a TOS violation or not ? Is it a safe way to show ads, or do I need to put them only on side of the blog ?
I you really want to know what happens, just do it... The permitted amount of units is stated in the TOS, so if you choose not to follow them, suffer the consequences. Anyway good luck, with adsense or another ad network....
Google suppresses the additional ads, but it is against their TOS. I use a quick/dirty api myself so that I never have more than 3 units. I'm sure there's some wordpress plugin that does the same.
I use now AdSense Manager for Wordpress. I doesn't cut the number of units to three, but at least has the option not to show ads in search results. As I can set to show only three posts on frontpage the problem is solved at least for some wp templates.
Nothing will happen , the 4th add you will place will not display anything but a blank box over there . After few hours or days you will receive one Google warning love letter for this work.