#1. You blocked it
This is a very rare case but do happen to few bloggers and forum owners who easily get obsessed with seo and immediately starts playing with their robots.txt not knowing when they block the google adsense site crawling robots.
Also some sites restricts access completely except you register fully as a member, this can hurt as google adsense bot will find it difficult crawling your keywords.
This in turn will hurt ‘cos google adsense uses your site’s keyword to display only ads that will be interested to your readers, when blocked some random ads that might be of no interest to your readers will keep displaying.
For site’s that requires compulsory registration, you need grant google bots access from your adsense publisher dashboard.
If you think or has already gotten the notification of ads being blocked by your robots.txt file, you need add this lines in your current and active robots.txt file to allow google and google ads bots crawl your site.
here is the code to add
#2. You allowed it
Normally you shouldn’t be monitoring your ads every now and then but at least for the first 3months of implementing ads in your blog, you need monitor it’s performance, play between different ads positions, block low performing ads and many of this best google adsense practices . But a lot of person will ignore this part once they place the ads there.
Some google adwords advertisers uses a lot of keywords when creating their campaigns, this is why you can easily spot a political advert on a car repair or phone serving blog. Believe me, most of your readers aren’t politicians and might never be interested in those ads.
Carefully block those ads that chooses to slip away from their supposed category via your adsense publishing dashboard. Also block those low paying ads that aren’t very interesting from mere looking at it.
Google has a lot of advertisers, even if you happen to block all those useless ads, they still have lots of targeted ads to display for your niche.
#3. Your ads are screaming to your Viewers
Even some loyal readers will find an adverts uninteresting when it screams so loud at them telling how it is there just to get you some bucks. This could be one of the reasons you aren’t getting enough clicks as your users are discouraged from clicking to them.
Also when your ads doesn’t blend fine with your blog background, it could be pictured as being too shouting.
Always place your ads close to your content (not in a deceitful manner) so as to get enough impression and to get interested persons see it very quickly too.
#4 You have too many of them
This is always the case with many newbie bloggers, they always get too excited once approved and immediately starts littering their blog with too many ads up to the point of getting their viewers pissed off. The bad user experience can not even give them enough time to stay on your site, let alone, clicking on adverts.
Place ads only where it will turn out a great user experience for your viewers and place only fewer ads too.
#5. Majority of your Visitors are tech bloggers or tech addicts
This may sound weird but it is the hard truth, many tech guys browses the internet with their ads blocking apps, addons and plugins enabled and might not even see your ads, let alone clicking on them.
This time around, the adblockplus browser addon is even becoming very popular among internet users and could account for loss in the number of clicks compared to what you would have gotten without it.
At times entertainment bloggers gets higher clicks than tech bloggers because of this factor.
Accepts private ads as that will replace the loss clicks that never happened ‘cos of the ads blocking addons
#6 You hijack all Possible keywords
Google adsense displays using the keyword of your website matching with the ones chosen by the adwords advertisers while creating their campaigns.
If you write on too many niches and targets a lot of keywords you may end up having too many random ads your users aren’t interested in.
Target fewer keywords that can easily convert and also learn to optimize your ads for clicks.
In addiction to all I have written so far on six (6) reasons you aren’t getting clicks to your ads, you need improve on your ads placement position and also take into account those pages that converts the most, also take note of the keywords that brings in the best value so as to build around them during your ads optimization.