Not to come as a surprise, but apparently too many ads on a page are bad for the visitor, and the advertiser. Interesting to note, however, is that having too many ads on your page can be bad for a publisher.

Nearly 30% of online adults surveyed and said they will immediately leave a website they perceive as “cluttered with ads”, and 75% who stay on those sites say they pay less attention to the ads there.
So too many ads is bad for the publisher, the advertiser, and the visitor. So what is the right number of ads to run?
The Right Number of Ads
Though respondents accept that advertising will appear on websites, the majority (52.6%), say they have low tolerance for any more than two advertising units per page. Another 27.3% say they will tolerate only a single ad per web page, and slightly more than one-quarter (25.3%) will tolerate just two ads per page.
So looking at these numbers, you should be looking to run about 2 ads per page. Looking at this blog, we have a lot more than 2 ads running, and looking at TechCrunch, the #1 blog, they have about 20 ads at any given point.
Too Many Ads Decrease Overall Messaging
The survey also found that ad clutter has a negative impact on consumers’ perceptions of an advertiser’s products and services:
* One out of two (52.4%) respondents has a less favorable opinion of an advertiser when their advertising appears on a web page they perceive as cluttered.
* One-half (56.4%) of women claim clutter negatively impacts their opinion of an advertiser, versus 48.3% of men.
* Women also are more likely than men to abandon a site that appears cluttered (32.1% vs 27.5% of men).
Ad clutter’s negative impact on respondents’ opinions increases with age. Less than half (46.8%) of respondents 18-24 years were impacted negatively by clutter, but nearly two-thirds (63.2%) of respondents age 55+ were unfavorably impacted.
