Plagiarism is rampant on the World Wide Web. I don’t know the conditions in other parts of the globe, but as far as Pakistan is concerned, I am sure 98% of the college and university assignments especially of technological and administration subjects get completed right from the Internet. That’s surely unethical.
But there are some places where in my humble opinion, Plagiarism is not so evil. One place is when you get a code snippet; let’s say for your site from some code repository site like codeguru.com or elsewhere. I consider it ok, if you don’t waste time re-inventing the wheel every day and go about focusing more on business logic and the innovation. This will not only facilitate rapid application development, but also give you more room to innovate and contribute more.
Yes, of course give the credit where it is due. There is no harm in mentioning of the fact that you have shamelessly taken the code from elsewhere, instead of wasting it. If you have obtained it from a public site, then even you don’t have to inform the author about it. But you should also give back something valuable to the community. That’s my take, what’s yours?