Yes you are right, the ads which has highest bid will be appear on the top of the adsense unit and remaining will be shown with respect to lower bids.

the ads which has highest bid will be appear on the top of the adsense unit and remaining will be shown with respect to lower bids

Not necessarily, the bid price is an important factor, but Quality Score and CTR are also taken into account. Which means the first ads shown should earn you more, but they are not necessarily the ads with the highest EPC.

Here is more info:
[adsense.blogspot.com...]

Yes you are right, the ads which has highest bid will be appear on the top of the adsense unit and remaining will be shown with respect to lower bids.

If that is so..then how come MFA ads comes on top? people say that MFAs are worth to block, so if we block them that means we are blocking our highest paid customers?

the ads which has highest bid will be appear on the top of the adsense unit and remaining will be shown with respect to lower bids.

That's never been the way. Where did you get your info ?

You never get to know, and that is how it should be, otherwise fraudsters will have a field day.

You never get to know, and that is how it should be, otherwise fraudsters will have a field day.

Then how come people say here to block MFA sites? and almost everyone support that here. I too have blocked many.

If you never know who is paying you best, how can you point that MFA site ads are giving you less money?

the ads which has highest bid will be appear on the top of the adsense unit and remaining will be shown with respect to lower bids.

I believe that was the case when AdSense first started however I'm fairly sure that isn't the situation now.

In the past, we have been told that the highest paid ads are always shown first. Unfortunately, that certainly is NOT the case now, if it ever was.

A few weeks ago, a "good-paying" page of mine started paying me less than 5 cents a click EPC. I blocked all 3 ads that were showing on the page (250x250). Immediately, I started seeing an EPC of over 50 cents, and it has been that way ever since. What can I say?

What we are told, and what is fact, are two different things.

There are MANY factors that determine ad serving. Some we know about. Others, we do not. Especially, the experimentation. Google is always testing various factors, and oftentimes, multiple factors simultaneously. Even the fonts won't hold still. This is what has rendered OUR testing ineffective and useless, for the most part. Now, I just pick what I like, and forget about it.

Then how come people say here to block MFA sites?

To improve the quality of the experience for your site visitors?

FarmBoy

If you never know who is paying you best, how can you point that MFA site ads are giving you less money?

An MFA site is an MFA site. No matter what they pay, they get blocked once found. I'd rather be paid less and point to a real site worthy of being part of Adwords than be paid more for sending someone to a crap site that gives little/no info.

Note that besides all of the factors including bid price there is some ad rotation going on. Lesser quality/bid price ads still show occasionally.

If this rotation didn't occur then only a handful of adwords ads would ever be shown on a particular page.

I see dozens of ads appear over time. Some days a page will get multi $ clicks and the next next it will be a nickle.

In an ideal world, the ads that earn you the most (not that pay the most per click) are the ones that are shown first.

The reality is that Google has a lot of ad inventory, and they want to get payed by all their advertisers. Putting an ad with lower payout first might be the only way those ads ever get clicked, while a better ad might get clicked fairly often even at a lower position.

They also have to balance out the ads for adwords customers who have a set ad budget. If my budget is $200/day, Google doesn't want to blow through that in the first hour of the day, even if my clicks pay the most.

I think there are a gazillion different calculations that go into effect every time an ad gets shown and then again when it's clicked on. And some of them would likely be entirely different five seconds later. I'd be amazed (and mightily impressed) if anyone could successfully reverse engineer that.