I've seen in my blog website stats that some of the visitors disabled javascript! How's that possible? This means that they don't see the google ads?
You can disable this in Internet Explorer in the Security options under scripting. In Firefox, you toggle javascript on and off under Tools->Options->Web Features In Opera, you toggle javascript on and off under Tools->Preferences->Advanced->Content The problem is that while most javascript is safe, pe0ople keep trying to develop exploits. There have been times in the past where Microsoft and others have advised people to shut down javascript until new browser versions were released to avoid being hurt by exploit code at malicious websites. Some people just never turn it back on. Things like Vista promise a change for users by forcing MSIE to operate with reduced privileges. But, as *nix users know, even that is not an absolute guarantee of safety as black hats work on exploits with privilege escalation code.
But google doesn't provide nonscript based tags. So to see google ads, visitor javascript must be enabled.
I realise google ads are js-based. Hence, I wrote 'non-js advert'. Just so you know, there are many advertising networks out there, not just adsense, and some of these have a non-js version of their ad. Or you can just write an advert for one of your own sites. To just rely on one advertising network, well as the saying goes - "don't put all your eggs in one basket". Broaden your horizons.
Why would you care if a visitor disables javascript or runs ad-blocker? These people don't want to see ads, they're not going to click on them, they have no desire to buy from the people paying you to place ads. It is a good thing, in my opinion, you're not wasting impressions on people who aren't going to click anyway. In my opinion, CPC model advertising will change over time, it has to. Eventually more people will become AdSense monetized publishers, and the more people that use AdSense, the fewer the clicks will be. Now is the time to take advantage of building your quality traffic -- real readers who are truly interested in your topic AND what your advertisers sell. In the long run, building that kind of quality site will attract "real" advertisers outside of monetizing networks who want to be part of your site. When an advertiser comes to you to place ads, you can negotiate how you send them traffic. I know of an advertiser that openly asks their publishers to say "Don't forget to click HERE to shop at GreatAdvertiser's site!" and the like.
You can use services such as amazon and clickbank (both are pay per sale) or valueclick (PPC). There are bound to be others.