Ads are a funny thing, I don't hate them like some people do, there is a reason for them. Ads are how a webpage can be supported, without you needing to pay for it, so in general I do not use ad blocking software, because I feel that I owe the owner at least a few ad views for using their site. However there are a few things that are never okay, ever, for ads to do:

1. Thou shalt not have ads the cover the entire page, blocking the content.
2. Thou shalt not make ads that play any kind of sound without my explicit permission.
3. Thou shalt not have ads which expand based on mouse hover events, only on clicks.
4. Thou shalt not advertise the your website which I am already on. Self-promote in a more subtle way, it's far more effective!
5. Thou shalt not make the entire background of your page into an ad, such that if I click on it I will be taken to another page.
6. No advertisement should have the style of position: fixed; unless it is within an appropriate (useful) element that is fixed for a useful reason.
7. Thou shalt not display ads for porn, unless you are a porn website. Even if your content is adult in nature, your ads should never be more explicit than you are.
8. Thou shalt not create pop up ads.
9. If you can not help yourself, at least never create popups that are not in focus (pop-behind).
10. Under no circumstances should any ad (or any part of your web page for that matter) use the alert(); function. EVER.