While this isn't "official" information, here's what some of the TCs in the AdSense forum have been noticing much more of over the last six months to a year. Blogs and websites containing some subjects are not being approved, even though they might contain originally written articles.
And to give a truthful answer, I'd have to say there isn't anything in the policies we can really point to and say "this is the problem" because the problem seems to be the subject matter the blog/website owner chose to write about. So, some of the most rejected blog contents we've noticed over the last year (in no particular order):
- technology - software reviews, gadgets, mobile technology, and any similar subject
- blogging - blogging tips, blog how-tos, blog coding etc.
- online marketing - make money online, how to earn money on line, sites built around affiliate contents
- jobs, resumes - sites listing job openings, job searches, resumes etc.
- education - sites containing educational papers, exam results, sample exams and questions etc.
- coding and programming - sites giving instructions on programming and programming languages, possibly because basic coding and programming languages aren't considered original contents.
- health - sites with widely general health information (much of it not sanctioned by health professionals) If you aren't a doctor or certified health professional, it's best not to write about it.
- hollywood/bollywood gossip - too many of those already, and most of them contain nothing new or different than the others, and also often contain a great deal of copyright infringing materials.
- newspapers/aggregate sites - almost none of these appear to contain original contents because they get their news from other news feeds, or pay to use contents from other news sites. Paying for it means it doesn't violate copyrights, but it's still not original and it still is duplicate contents.
- wallpaper sites - enough said; everyone knows what these are and nobody needs anymore of them. Almost none of these contain original contents of any kind.
- facebook knock-offs - sites that look like facebook; sites that use aggregated contents from facebook (statuses, likes, etc.). None of this is original contents; some it may violate not only copyrights, but the privacy of some individuals.
If your site isn't on the first page of search results for your content keywords, you'll be down near the bottom of the pile providing similar contents to the big review sites, so this is a difficult area to break into, and one which Adsense doesn't appear to want any more of at the current time.
Of course, things change because nothing ever stands-still but if you plan on applying for Adsense with a tech-related site, you may be disappointed. Unless your site is spectacular by Adsense standards, it would probably not be accepted. So, what is "spectacular" - that's one I honestly can't answer but unless your site is better than one of the top 10 or so in the world of techmology sites, it probably isn't going to be "spectacular" enough for Adsense right now.
Some of those subjects in the list actually do violate the program policies (ie: educational materials) and job sites usually end up containing duplicated contents because, let's face it, how many jobs are out there and where are all these sites getting their job listings? From the same newspapers, the same job boards, and the same human resources sites, making the contents unoriginal and really not that helpful or suitable for Adsense. Now, on the other hand, if you do own your own company that finds jobs for applicants, and finds applicants for jobs (ie: often known as "head-hunters") and you have jobs that nobody else has, you might have something original enough to get approved. However, that being the case one would expect you also own a proper website, and not just a free blog, right?
One other thing to note which I think a lot of publishers overlook. IF your site is one of the above and DOES NOT get approved when you submit it to Adsense what that means is that it isn't suitable for Adsense. And if it isn't suitable for AdSense, then you DON'T put ads on it later if you get approved with another website. That's just asking to get your account disabled.
by J. Gracey Stinson