It can be, yes.
If you credit the original author, such a notice might be sufficient in SOME cases. If the quoted source is current and still commercially valuable, then no. The reason for copyright is to protect income primarily. So if you think it will not harm the author financially, you can risk it but is still technically illegal.
If you post a copy of a movie or CD on a public forum, you are breaking the law. This also applies to text from a book or magazine or any intellectual property. In all these cases you have to notifiy the the author or the agent and arrange for permission to do so.
If you put quotes around it or include it in a bibliography, then it is not plagiarism.
Not necessarily as long as you put that you found some of the info on answers.com somewhere on the project then you will be good. Note: You must sight your sources in all projects. Copying From Wiki answers is illegal with out attribution.
No, it is not necessary to put the definition of plagiarism in quotation marks unless you are directly quoting a source. Otherwise, you can simply state the definition in your own words or paraphrase it.
no one "provided" him, it was based on his discovery and science
Not directly but somehow it does expose info of you but it all depends on what info you put in your Facebook account.
When your manoeuvre is to source answers on the web, you must be careful to avoid plagiarism.
As long as you cite your source, it is not considered plagiarism. But most teachers do not allow you to copy a page, even if you cite it.
Global Plagiarism is when you plagiarize from one person! Patchwork Plagiarism is when you plagiarize from couple people and put it all together. Just like how you do a patchwork, you sew a couple of small pieces to make one big thing!
plagiarism
No, as long as you credit the source you have used and if it is a direct quote you have used quotation marks then it will not count as plagiarism even if you did copy and paste it.
The prefix of "plagiarism" is "plagi-".
Plagiarism and copyright infringement.