Every keyword has some traffic. Even the super long tail ones will get some broad search traffic from google once in a while.
Yes I know what your argument is with this idea. You may get lots of traffic but it wont convert or very little traffic for the good targeted keywords.
I have had this problem since I began building sites several years ago. Several sites that are celebrity sites and joke sites and image based sites which are very difficult to monetize where getting double the amount of traffic with very little effort. So I tested many different ideas on monetization with them seeing what converted the best.
These types of sites usually attract information seekers and not solution seeking buyers. These sites are popular with Facebook and other social media sites which means they will get lots of likes if i set up a fb fan page.
You can still make money from these sites however. Below I have listed some ways that I have generated income from them.
1)If you get enough traffic like 500-1000+ day you can sell ads on your site
2)google adsense and other text based advertising performs very poorly usually around .5% conversions sometimes even less. Depends on placement, color and exact topics on your site however. Infolinks has worked better for me than google adsense with these sites.
3)Go wide with marketing - promote discounts and sales on popular items like consumer electronics like ipods or clothing at well known and trusted stores like amazon, apple store etc.
4)Go Narrow with marketing - promote individual products somewhat related to what you think your core audience is.
eg. image site about bikini models. Obviously male, probably younger. May like dating advice, mens clothing cars, university courses, music electronics etc. For each one of these you can make ads
5)redirect traffic to another one of your sites that is more targeted like in the example above like a mens fashion ecommerce store or review blog.
6)Always be building a list. By far the most money I've made is via list building on these sites. Give something of value in exchange for their email address. If its a pdf on dating advice then obviously they are interested in that
Another thing to keep in mind is that when people go these types of sites which are often image based they often click thought things very quickly so their on page time is less than it is with an article. This is especially true with image sites. You have to grab their attention so don't use subtle little 250x250 boxes. Use huge boxes that have a jarring color so there is no way they can miss it.
I have found that for regular articles sites block font on white background is best but for image sites black background is better.
Hope some of these ideas have helped. Let me know what you think.
My next post will be on customer profiling. This is the key to maximizing revenue from any website if your goal is to get them into a sales funnel. Of course the other way is to trick out your site/blog with many forms of advertising with the only real intention of getting them to click on ads. JohnChow.com is an excellent example maximizing ad space. If you get his free ebook he explains all the forms of monetization of his blog.