How ads look like this ?

You have to know one thing about ads that how they look like? And How to Format them that you use in your websites in future?
Google provide different types of ads the list of some popular ads are listed below.

Adsense for Content
Adsense for Search
ADsense for Mobile Content
Adsense for Feeds

90% of the advertisers use fist two type of ads which are listed above because they are very useful to maximize profit. Adsense for Content: Adsense for content has further five type of ads:

Text Ad
Image Ad
Link Unit
Video Ads

Gadget Ads How the above ads look like? See in the this below link

https://www.google.com/adsense/static/en_US/AdFormats.htm