It is noticeable that most of the newbie bloggers have the only intension of Earning Money by Blogging. They do not care about giving any value to the readers. As, Adsense is the major source of Income for majority bloggers, They start copy-pasting articles from other Sites and insert the Adsense codes on their sites. They expect to make money through it!
In most of such cases, if such sites are used for registering the Adsense account, the Accounts are not approved. But it does happen that people get their Adsense Accounts verified from good Article sources and then put their Advertisements on such cheap copied content.
Also, there are a lot of Softwares and Plugins which allow publishers to create AutoBlogs. Auto-Blogs are basically blogs which get updated automatically using the content from other sites. When, pre-mentioned websites get updated, the content in the Autoblogs is also updated.
So, the AutoBlogs have continuous source of Content without any moderation by the user. We can call such sites as a hub of Copied Auto-generated content. (they do give credits to the original source most of the times)
Many Publishers use Adsense Ads for monetizing such blogs. But, according to Google Adsense policies, it is not allowed. The recent Blog post on the Adsense Blog clearly mentions:
We don’t allow sites with auto-generated or otherwise unoriginal content to participate in the AdSense program. This is to ensure that our users are benefiting from a unique online experience and that our advertisers are partnering with useful and relevant sites.
It must be taken as a warning by publishers who use Google Adsense on sites with Copied or Auto-generated content. As the Adsense team has made it clear, your Account may be in danger. So, take proper care of your Adsense account as getting banned from Adsense may be the worst set-back in your Blogging career.