is there a line not to be crossed.

Regarding drawing attention to adds.

[nippi]

I've seen some sites whose adsense ads are done so to appear to not draw attention to them, but the result is to in fact draw attention to them.

eg, adds done in exact same colours as navigation, animated gif or flash near the adds.... not saying click this add... but certainly drawing attention to that part of the page.

Its done well, the sites look great, and I suppose you could argue its not done to draw attention to them, but is clearly done to ensure the user does not see the adsense contents as ADDS, more as just site content to be clicked on.

Illegal or not?

[Tearabite]

it's called 'blending', and Google encourages it..

"drawing attention" is like "CLICK MY ADS TO SUPPORT MY SITE", or something like that..

FWIW, if you blend your ads too much, and people are 'tricked' into clicking them, then never by anything, SmartPricing will kill you.