It’s common for businesses to use intellectual property created by another party. This is accomplished by obtaining a license from the owner. A license is a grant of rights to use someone else’s intellectual property for a term — with a reversionary interest. In other words, there’s a set time frame in which those rights are granted, after which all rights revert back to the owner.
When using someone else’s content, it’s critical to obtain a license and to attribute it according to that license. Of course, there are exceptions, like where there is no commercial interest. George Lucas would not sue a sixth-grader for using a Star Wars figure in their diorama for science night — but using someone else’s content and posting it to a blog on your business website is another story.
For example, if you use unlicensed, watermarked images from Shutterstock, you can be held liable. There are also people referred to as “copyright trolls” patrolling the internet for infringement of intellectual property they own.
You can insulate yourself from infringement claims by taking out the right license.
Note: Even if you’ve taken a “free” Creative Commons license, make sure that you’re providing the right types of attribution (sometimes a link back to the original site, etc.).
As long as you are following the guidelines and requirements under those licenses, you’re not infringing. If you’re not following them, you could be open to copyright infringement claims.