When licensing something to a broadcaster, it will generally include "updates, repeats, re-airs and in context promotions, and in promos released to affiliates, partners, and licensees, distributed worldwide, in all media now known and hereafter conceived or created, including home video and DVD and Internet and broadband distribution." An in-context promotion in this case just means a teaser.

Say you send a video of your cat falling off the couch to America's Funniest Pets. Signing this agreement would allow them to use it in a show, re-air the episode, use part of your video in a teaser or other promo, distribute the show and/or the promos worldwide, use it in a different show (say, a compilation of the top ten cat videos of the past year) and cut promos of thatfor worldwide distribution, in any format, forever.

The "in context" part is important, though: it means you're not giving them license to use your cat video in any other type of project.

Trademark laws protect "words, names, symbols, sounds, or colors that distinguish goods and services from those manufactured or sold by others and to indicate the source of the goods. Trademarks, unlike patents, can be renewed forever as long as they are being used in commerce." Unregistered trademarks are a bit harder to enforce than registered, but last as long as they are being used. Trademarks may be registered in states or countries or both.

The (TM) symbols for TM and SM are completely optional and require no registration. However, there are advantages to having a state or federal trademark registration, including the fact that it will tell others when you first used your brand, which can be important in priority disputes. Valuable marks justify getting professional advice.

To learn more - and there is a LOT of info - check out the United States Patent and Trademark Office Home Page (their glossary is a good place to start) and the U.S. Copyright Office in the Library of Congress.

Here is more input:

• Depending on your local state laws, trademark registrations have different lifespans and can either be renewed or not. If a trademark is registered it is only registered for a certain period of time and then the owner decides to renew it or not. As long as you continue using a trademark, and were the first to use it, you can enforce it in state or federal courts, whether or not it is now or has ever been registered in a state or federal proceeding.

• The © copyright notice and ® registration mark have nothing to do with state registrations.

• Any time you claim rights in a trademark, you may use the "TM" (trademark on goods) or "SM" (service mark) designation to alert the public to your claim, regardless of whether you have filed an application with the state or USPTO. However, you may use the federal registration symbol "®" only after the federal USPTO actually issues a registration, and not while an application is pending or after registration expires. Also, you may use the registration symbol with the registered mark only on or in connection with the goods and/or services listed in the federal trademark registration. Any major change to the mark or the goods/services will require another registration. Federal registrations require periodic maintenance fees (i.e., every 10 years).

Yes, "Night of the Living Dead" is a good example, which fell out of Copyright after they failed to note a copyright notice in one of the film materials.

From Archive.org: "If the work was made in 1923 or earlier, it is probably public domain and can be uploaded. NOTE! Restored versions of the film or new soundtracks for silent films can have more recent copyrights that are still valid - usually a copyright notice for a new soundtrack or restoration will appear in the film. For works made from 1923 to 1949, post a question to the movie forum on this site [at archive.org] before you upload. The copyright could have been renewed and there isn't a way online to check a film's copyright status. For works made from 1950 to 1963, you can check the title at the Library of Congress Copyright Database for copyright renewals: http://www.copyright.gov/records/cohm.html . This will list copyright renewals for most films." A video may fall under public domain if: (1) the term of copyright for the video has expired; (2) the author failed to satisfy statutory formalities to perfect the copyright or (3) the video is a work of the U.S. Government.

Most countries' laws are very similar, based on the Berne Convention. The US and several others have extended protection from life + 50 years to life + 70 years for works of a single creator, and some countries have optional formal registration in addition to the automatic protection demanded by Berne.

That being said, not all countries are equally conscientious about enforcing their IP laws.