Copyright on the web seems to be a murky topic. Since the web is worldwide, there are different laws in different countries, and different views on intellectual property. And this means that what is stealing in one country might be a compliment in another. If you are going to create content and put it on the web, you not only need to understand how you can benefit from copyright but also how it might be harming you.
Copyright Protects Artists
Many creative artists feel that when their work is taken without payment, they are economically hurt. To put it another way, when content including art, music, writing, and photography, is taken and used without permission, the creator's ability to create more content of that type is reduced because they have not been compensated for it. This is especially true on the web where many sites are monetized by advertising, and advertising needs to be seen (and clicked on) to make any money.
Here is a common example:
A blogger writes an article that becomes very popular. It is shared on Facebook, tweeted, pinned on Pinterest, and goes viral on the internet. The blogger notices a headline that reminds him of his article on another website and clicks through to see what it is.
It turns out that that bigger website has copied the article word-for-word onto their site. They included an attribution at the bottom back to the blogger, but didn't include a link. And even if they had included a link, why would anyone click on it? The entire article appeared on the bigger site.
If you're thinking that this doesn't happen, let me assure you that it does, in fact, it happened recently when a large entertainment site did ripped off some bloggers without even crediting them.
A blogger or other artist who has creative work on the web can protect themselves and their work through copyright law. In fact, works created after 1989 (in other words, nearly all new web content) is automatically copyrighted by the author even if there is no copyright notice on the work.
But Does Copyright Really Protect Artists?
While your work is automatically copyrighted by you even without a copyright notice, does this help you? Copyright does not guarantee that you can collect damages in court if you are infringed upon. In the United States, for example, only authors of works registered with the U.S. Copyright Office may collect damages without proving economic harm. If you haven't registered (and paid the fee for) your copyright, you can require other sites take down the infringing work, but you can't sue them for damages.
And artists have to do all the work themselves to find copyright infringement and get it removed. This can be an expensive endeavor, and one that takes a lot of time. Visual artists like photographers and painters used to have a harder time than writers finding infringements, but with tools like image search it is getting easier and easier to find even visual copyright infringement. But the time required is not inconsiderable and might be better spent creating new content rather than fighting infringements.
I used to spend one day a week looking for and dealing with copyright infringement of my work. I used tools like Copyscape to find infringments, and then would write long letters to Google and other advertisers asking to have the advertisements removed from the guilty sites. This was my least favorite day of the week both because of how hard it was and how upset I would get at the blatant and usually uncredited theft that happens constantly on the web. I had some of my oldest articles copied into “free content” websites and then these would be used over and over by hundreds of people. Most would happily remove the content once they learned they were violating copyright, but the toll on my mental state was huge. When I forgot to do the work two weeks in a row, I noticed that I was much less stressed and decided right then that it wasn't worth it.
Copying as Marketing
I watched a video of Neil Gaiman discussing copyright piracy where he proposes that copying, especially on the web is really a form of sharing which ends up being marketing. If someone copies your work, and this inspires someone else to look up your content, you have just gained a reader, not lost a sale.
I would argue that most websites that you've ever visited you've visited because someone recommended it to you or because of some type of copying. You can get recommendations via sharing sites or word of mouth, or just links that you click on on other sites. And even search engines are guilty of a form of (legal, because of fair use) copying. They copy your headline and often the description or text from the page and put that in their search results.
When someone copies your work (with or without permission), they are increasing your reach and showing your work to someone who might not otherwise see it. And if that person likes your stuff, they will seek you out to find more.
Don't Get Me Wrong
As someone who pays for food with the advertising revenue made from you reading my site on About.com and the clicks to ads those page views generate, I would much rather you not copy my work. But if you got here from a copy of one of my articles then I'm glad to see you. I hope you'll stay a long time, perhaps buy one of my books, and learn as much about web design as you can from me.