Strict definition: more than three consecutive words, I believe.

I have a similar thought as Jake Lewin. I write a weekly column for a local paper and often publicize events. I have from time to time gone to an organization website, typically a not-for-profit in my case, and copied text from the mission statement or description of the organization. While in every case I have reworded the text I occasionally use specific phrases from the webpage. Is that plagarism? Should I identify the website as the source of the information?

Listening to this I couldn't help think about all the press releases that are often run in whole or in part without editing or clear attribution. While the author of the release is essentially asking for them to be used, doesn't the news outlet owe some form of disclosure here? Is the practice or running press releases showing some tacit approval for printing other's words? I would guess that very few people understand the extent to which text in papers comes from the press releases of others.