Plagiarism is difficult to define in a project like this, where most of the information that we're posting is from books, websites and other secondary source materials. The best way to define plagiarism may be to use the famous quote from a Supreme Court ruling on pornography: "I know it when I see it." The essential standard is: If it's obvious to a reader that your text is copied from another source, then it can be considered plagiarism. Copy-and-pasting text from a website into Diabetes Wiki is a bad idea, even if you change some words here and there.