AdSense isn't the unstoppable revenue engine for every eBusiness. Before I am taken out and flogged by the eCommerce pundits -- please let me explain what I mean in my defense.

I make revenues from AdSense at a very high click-through rate. I experience high click-through rates with AdSense without resorting to questionable tactics like tricking site users with photos (the AdSense trick and tip dujour).

So my perspective is from one who has made decent income from AdSense to fund aspects of his business like advertising seminars -- and outsourcing to his virtual assistants. Yes, AdSense is a legitimate and significant revenue source. However evaluate AdSense with some type of balance.

By now you may have heard about people like Joel Comm's six figure income with AdSense, or Jason Calacanis of Weblogs being on his way to generating 1 million dollars in AdSense revenue. Google's Ad revenue sharing affiliate program for publishers certainly seems to be an eSales Nirvana for many webmasters.

But there are obvious and not so obvious times not to use AdSense ads on your sites. Let's list - examine - and explain them below.

~~~~> 1. On Sales or Mini-sites

This is a no-brainer. If you are trying to sell a particular product that is important to your bottomline, you don't want AdSense ads distracting your customers from either joining your email list, or hindering your site's online sales process.

However I do see hybrid sites that are mini-sites or full scale eCommerce sites, with AdSense at the bottom of their pages. This might not be so bad since only 1% - 15% of your site visitors will either buy from you or fill out a form.

The thinking with this approach is you might as well make money from disinterested parties using up your server's bandwidth.

~~~~~> 2. SEO Business Sites

If your livelihood depends on search engine optimization or marketing for a living you might want to think twice about displaying AdSense Ads on your site. I can tell you this from personal experience. I once was on top of MSN for search engine marketing in my local area. I concentrated on my local area because I found people felt more comfortable hiring an eCommerce consultant locally.

One day my site fails totally out of the MSN index. After intense study I noticed that I obviously had a filter on my site from MSN.

I analyzed all the top ranking sites in MSN and noticed the only difference between me and the other top ranking sites was I had Google AdSense ads on my site. Someone at MSN felt that my AdSense ads, and perhaps to a less extent, my book on SEO, was getting a free ride in the MSN search engine database.

In fact I noticed that there were no sites with AdSense ads for at least the first 3 pages. Plus the sites with AdSense were only using 1 ad unit at the bottom of the home page (there were very few of them in the top 5 pages).

I knew it was strange to not have AdSense ads on the top Internet marketing sites. This prompted me to scan other industries where I noticed the same trend.

Many of the leading SEO gurus have sites that have been banned from the top listings by the search engines. It seems the more visible you become, the more of a target your sites are to the search engine auditors.

Some of my sites are still on the top of MSN with AdSense ads but that doesn't mean they won't also be targets in the future.

Let's face the facts. MSN and Yahoo! have competing ad networks to Google's, and this competitive situation is rife for a potential backlash against SEO sites with AdSense ads.

Many SEOs will point to exceptions to this position. However you have been warned!

Think about it, how long will MSN and Yahoo! sit back and watch SEO driven websites use their search indexes to fund Google? Did you know SEO in MSN and Yahoo(!) --- is much easier to obtain.

Therefore optimized sites are creating an ad sales wealth transfer from MSN and Yahoo into the pockets of Google! It won't be long before Yahoo! and MSN begin to devalue ranking on AdSense sites in their databases -- if not outright ban them.

If you are in the search engine business stay search engine neutral, or create multiple sites for different search engines.

~~~~~> 3. When AdSense Becomes Your Only Business Model

When you become so myopic in your thinking that you build a business solely on AdSense revenue -- think again my friend. Why build a business solely on the largess of Google?

I don't know if your realize it or not, but the sites making the real big AdSense money usually have a following that doesn't depend on the search engines. Internet mavens like Chris Pirillo or Joel Comm have been on the Internet a while and have followings for their websites. Therefore they can consistently make six figures with AdSense.

These content powerhouses are an asset to Google and not the other way around. But do you think Google is going to sit back and watch just anybody make big bucks off of their top rankings?

If you do a search on most keywords you will notice many of the top ranking sites are news sites, .gov sites, or .org sites these days. The only exception is in industries where these sites don't really exist like eCommerce industries (clothing, shopping, etc.).

No doubt in most industries you will notice a conspicuous scarity of AdSense sites in the top rankings. In other words don't bet your future fortunes on AdSense.

An IPO based on projections of AdSense revenue isn't in the future for the average eBusiness. Think of Google AdSense as supplemental income. Building a business solely on AdSense revenue isn't just silly -- it's just plain stupid.