Intellectual property (IP) 

 -- a term referring to a number of distinct types of creations of the mind for which a set of exclusive rights are recognized—and the corresponding fields of law. Under intellectual property law, owners are granted certain exclusive rights to a variety of intangible assets, such as musical, literary, and artistic works; discoveries and inventions; and words, phrases, symbols, and designs. Common types of intellectual property rights include copyrights, trademarks, patents, industrial design rights and trade secrets in some jurisdictions. -- Wikipedia

Why am I even talking about this?  Well, it seems to me that many folks believe, that the thoughts and creations of others are "fair game", that somehow because they like an idea that they can present it as their own. I have seen this done rampantly in the new age movement where gurus adopt the flavor of the month theory or the latest trend and begin to use it or talk about it in their workshops and conferences as if they originated it, without any references to those whose work it truly was.  I have heard many of these individuals state that 'everything is free', no one really owns anything, and/or since we are 'all one', there is no difference between you saying it and me saying it.  I don't think so.

Basically, intellectual property includes, but is not limited to, a person's thoughts, ideas, concepts, designs, and plans that they have used, or plan to use, to create something real and tangible in the world for their own purposes.  The intellectual property may be tangible or intangible.    This makes the 'ownership' and use of thoughts and ideas even more difficult to decipher. 

For me, the distinction with ideas and thoughts, as opposed to products or technology or art, is a bit like the difference between paraphrasing and outright plagiarism.  If I were to copy a person's dissertation and publish it as my own with little or no changes, then that is obviously plagiarism and a theft of intellectual property, identity, prosperity and possible future earnings of that other person.  If, however, I extract a few ideas, edit, rephrase and add my own understandings in a paper then it might or might not be definable as a theft.  Maybe some additional data would help?

Such creations of the mind and thoughts of a person may or may not be offered for sale, may or may not be distributed, and may or may not be described or explained in sufficient detail that another person can duplicate it.  

In general, the creator of products marketed for sale to the public retains sufficient information about such creations to prevent competitors from duplicating them.

In medieval times,  inventions and artistic creations were financed by benefactors.  A patron paid an artist to live in residence and create art or music in exchange for living expenses and the raw supplies  to create.  An artist was paid to create a play or an opera or portrait, which then belonged to the patron who had commissioned it. The artist's name was attached to the work, but the owner was clearly understood to be the one who had paid for its creation.  The notion of intellectual property did not arise because there was clarity in who created the 'product', who paid for it, and who owned it and retained possession of it after the sale.

Intellectual property began to be important when the sale of a product was redefined to allow an owner/creator to sell the USE of a product for a specified amount of time, under specific conditions, while retaining ownership and final distribution of the product itself. This arrangement is most often seen in the software industry.

A customer does not actually buy Microsoft Office, for example, but rather buys the use of that software package under the license terms included in the package.   Microsoft retains ownership of the actual code used in the software package and does not allow for that code to be made available to other software programmers for their use in creating competing products.

The music industry has been prosecuting those who give away personally owned music on peer networks.  It is their contention that a music label retains ownership of a music CD or song after the sale in much the same way as software manufacturers do.

Where once the question of ownership was resolved at the point of sale, the question now seems to revolve around physical possession of it and whether or not that sale was for the product itself or for its usage.

The word, "proprietary", is often used to indicate that portion of intellectual property that is not shared when the product is sold, if it is sold, regardless of whether the sale is for total ownership or for usage alone.

 Public Domain materials and products are those items that can be used freely for profit or personal use.

Copyright and trademark designations have been applied to products sold in total or for usage according to a license. These designations 'mark' the product as the work of an individual or a company and not something that is widely available in the public domain.

Fair use - Laws have been passed to allow for the fair use of copyrighted work.  Please note that fair use does not include the right to make a profit off the work of others (selling it as if it was one's own work), nor does it include the the right to diminish the potential market value of the work.  In general, if one intends to use enough of the copyrighted material to produce a competing product, then this disqualifies that use as 'fair'.

17 U.S.C. § 107.  Notwithstanding the provisions of sections 17 U.S.C. § 106 and 17 U.S.C. § 106A, the fair use of a copyrighted work, including such use by reproduction in copies or phonorecords or by any other means specified by that section, for purposes such as criticism, comment, news reporting, teaching (including multiple copies for classroom use), scholarship, or research, is not an infringement of copyright. In determining whether the use made of a work in any particular case is a fair use the factors to be considered shall include:

1. the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes;
2. the nature of the copyrighted work; 
3. the amount and substantiality of the portion used in relation to the copyrighted work as a whole; and  the effect of the use upon the potential market for or value of the copyrighted work.
4. The fact that a work is unpublished shall not itself bar a finding of fair use if such finding is made upon consideration of all the above factors.^[1]

-- from Wikipedia

Please note:  If you are thinking of using copyrighted materials that do not belong to you, consult with an attorney for the specific conditions of "fair use".