Let’s think for a second about the difference between copyright violations and plagiarism, a helpful distinction to keep in mind when discussing how this stuff works online:
Copyright violation is a legal issue. Because we want people to make awesomely creative content (Words! Music! Art! Philosophy! Etc.!), the United States has laws that allow content creators to control how their creations are used for a certain amount of time. The law states that people have an automatic copyright on their own creations. Anything you create is automatically copyrighted once it is fixed in a medium. When you are writing a paper in your word processor and save it to your hard drive, it is copyrighted. Take a picture with your digital camera or phone. The moment it is saved onto your camera or phone memory, it’s copyrighted. No copyright notice required on your part.
Copyright gives content creators a chance to make money from their work and hopefully continue making more. As a copyright holder of a creative work, you control how that work can be redistributed and whether or not it can be modified. There are certain circumstances where it’s legal to use copyrighted material in ways beyond what the copyright owner allows. These are called “fair use” situations, but let’s not get into that yet.
Plagiarism is an ethical issue. While violations of copyright are determined in court and are mandated in laws, acts of plagiarism are often not illegal at all (though they can be). Instead, plagiarism occurs when someone uses content (usually text, but not necessarily) in a way that isn’t allowed by the community (e.g., writing in a school setting or academic publishing) in which the content is being used.
With that distinction in mind, we can see how using text or images found online can violate standards of copyright, plagiarism, neither, or both. The same basic principles you use for your college research papers apply when you write for the web. The short version: if you use other people’s words, put quotation marks around them; if you use other people’s words or ideas, acknowledge them. Similarly you should also acknowledge your use of images or other media elements. (See the next section for more information.)
In terms of what can be quoted, there may be legal issues involved, but generally you are allowed to quote any material that is freely available on the web in the same way that you can in your research writing. By convention and respect for the copyright holder, though, it’s a good idea to quote only a few lines of text, or at most a single paragraph. You may also quote small portions of text from print sources. Copying all of the text of a source (print or digital) into your text would be a copyright violation.
There are a few differences between how you handle citing sources in a research paper and on the web. When using quoted material, some bloggers use the rich possibilities of the web to do more than just use quotation marks. Blogging templates often provide a way to indicate long quotations through some design element: a different type font or size; a text-box of some kind; a change of background color; large quotation marks; etc. If you use many quotations in your posts, you may want to think about using some design element to set off those quotations visually.
Good news for bloggers in all this. For acknowledging source authors, you are let off the hook in terms of MLA Works Cited pages or APA References pages. Yippee! Instead, bloggers normally acknowledge authors by linking to their articles or website. If information is taken from a print source, it’s pretty standard to link either to the Amazon page for the particular book or to its page on a publisher’s website.
Nevertheless, if you’re writing in other web genres, you may need to provide sources (for example, Wikipedia provides footnoted references). And if you are are writing for a class—blogging or not—don’t assume that your teacher doesn’t want a Works Cited or References list. You would be wise to ask.