You do not approve ads. As you wrote:
...they will show even if I don't approve them.
You block ads. Why? That is really up to you. The two main reasons I block ads are:
1- to prevent competitors from showing ads on my site and stealing users.
2- to protect my brand. There are a lot of really spammy low quality ads out there, many of which I don't not want user's associating with my website or brand.
It is important to know that blocking ads has limited effect and come at a cost.
Blocking an ad removes the "buyer" from the auction allowing the next highest bidder to take its place. So, the next ad will pay less, and assuming that spam ads appear as a result of a lack of demand (a safe assumption) then the next ad may be equally as spammy.
What to do. The best option is to remove the inventory from the auction completely by using the ad balancer. It is not perfect but helps reduce the low quality ads.
I have thousands of ads to review.
This is case when you don't review your ads for a long time. The ad review shows you the ads that appeared over the last 30 days. So if you haven't reviewed ads in 30 days, then you have 30 days worth of impressions to review. If you review on a daily basis, you will only have a days worth of impressions. Also note that if the exact same ad appears on your site 100,000 times it will only appear once in ad review. So if you have steady advertisers that buy a big portion of your impressions you will have relatively fewer ads to review. If you have no specific interest in your site you will likely have a lot of ads to review. So a daily review, can provide you a good feel for the current interest in your website.
