Just now i saw in one website , google ads are displaying without ads by google tags at the bottom.I want to know ,are they modifying ad unit for displaying ads without ads by google tags.I think this is against TOS. If so, How they are doing it. Does any one knows????????
Can you provide a URL? Maybe something is just covering it, Modifying the ad code can never hide the "ads by google" thing.
if the website you mentioned is popular......they probably have adsense premium account, which allowed them to change almost everything... for example... http://www.imdb.com/ and http://www.tv.com/ ... see their adsense page http://www.imdb.com/title/tt1013752/ (right top) http://www.tv.com/story/13858.html?tag=hotspot;gumball;1 (below the user comments)
You should have 100000 (1 lakhs) page views per day to become a premium publisher. Usually google will mail you with application form after you reaches the requirement.