Do you post news articles on your blog from major news sources and site the source? Do you do it more than you write original content? How about market reports? Do you copy and paste the same template and then change just the community, town and prices?
Now, it's ok to once in a while repost some great content if you feel it helps your readers and as long as you link back to the source of the article but if you do that more than you write your own original content you are diluting your site.
The more content you swipe from somewhere else the more your site looses it's originality and authority. If, in reading fabulous news articles you think that the information would be valuable on your website and simply copy and paste the content over, you're diluting the authority of your site as having any original content. If you're blogging on your own with your own original content once or twice a week or even once or twice a month but copying and pasting news articles from other websites and sources more than you're creating your own original content, the site will be unbalanced as an authoritative resource for what you're actually selling.
It's completely fine to link to articles that have related content and Google actually encourages it if it helps the reader understand what you're trying to say in your original content. You are giving your reader as much information on whatever subject your writing on as possible. However, if you continually copy and paste entire articles into your own blog post, even with a link back to the source, you are slowly lowering the authority of the website as a whole.
The same goes for market reports.
Market reports can be very dull but they also can be very informative if done correctly. However, if you are simply changing the community or tow and all the numbers but leaving the basic information the same in every single market report you do either weekly or monthly, Google will still count it as similar and duplicate content. Each market report needs to be unique and custom. I know it's a pain, especially if you do the same reports month after month, but throw in some new content about the area, local events that month or activities that you haven't previously mentioned. Also, add photos of the area each time and label them differently with a unique ALT tag.
"Duplicate content is any content on another website, right?
Wrong. Or at least it’s not that simple.
Duplicate Content is the same or very similar content on the SAME website." [Source]
So you don't want those market reports duplicated over and over again on your site.
Here's what you can do about news articles.
There are many sites that have great content that you may want to share and most of the time it's fine as long as you put in a source link (but check with TOS of the site for full rules on sharing content). But, the better way so as to not dilute your blog is use bits of the information in your own blog about the subject. Put your own opinion and twist on the topic and use segments of the articles in quotes so readers know you are quoting the actual article, like the quote above from Search Engine Journal
I believe the best way to use great content on your site is to provide an excerpt and then link to the main article for the rest. Give your readers a good paragraph about the topic but then put a link in to read more from the source. This won't dilute the amount of content on your site (as long as you producing your own content as well) and yet you are giving your readers great information even if you didn't write it.
Syndicating is different than duplicate
“If you syndicate your content on other sites, Google will always show the version we think is most appropriate for users in each given search, which may or may not be the version you’d prefer.”
Syndicating your own content is fine as long as the original resides where you want it. Good content should be syndicated in the appropriate way. This can be for your own content and other people's. Maybe you have a great blog on your ActiveRain site and want to syndicate it to your tumblr account. Give readers a taste of what the article is about and then a link to read more over where the information originated.
The take away here is balance. Don't be so wrapped up copying and pasting great information that you forget that readers want to hear from you too! Give us your take on the topic, syndicate it on social media or give us just an paragraph or two of the article but don't just copy and paste for the sake of building your site or boosting another's content.