The trademark symbol should be used when a brand name, logo, or slogan is registered as a trademark to indicate ownership and protection of the intellectual property.
The registered trademark symbol should be used when a brand name or logo has been officially registered with the government to protect its ownership and rights.
Facebook is a registered trademark, which earns it the right to use the ® symbol.
Assuming you are referring to the social networking website, the name "twitter" is a legally registered trademark so it should be used with the ® symbol.
The "TM" symbol, often printed small next to a picture or piece of writing that a company owns, stands for trademark. The trademark symbol can be used for any piece of property that one feels they have ownership of, even if it has not been filed with a patent office.
The Unicode for the Trademark Symbol is a symbol used to make the assumption that the previous mark is a trademark (a trademark is a recognizable sign of a particular company).
When the logo has been trademarked (that's what TM stands for). If you want to trademark something, check out this article: http://en.wikipedia.org/wiki/Trademark
The trademark symbol (™) is typically placed immediately after the trademarked word or logo, without any space. For registered trademarks, the registered trademark symbol (®) is used in the same way. It's important to use these symbols consistently to indicate the status of the trademark and to provide legal protection. Always ensure that the symbol is used in conjunction with the trademarked term it represents.
Trademark. The trademark law prevents companies from stealing a product name. The Trademark Symbol -- > ™
The (R) symbol is used to indicate that the preceding word or phrase is a trademark or service mark that has been registered with the trademark office.
The copyright symbol is used to protect original works like books, music, and art, while the trademark symbol is used to protect brand names, logos, and slogans. Copyright protects creative works, while trademarks protect brand identity.
After.Chicago Manual of Style, 16th Edition. 8.152 - Trademarks...Although the symbols...(for registered and unregistered trademarks, respectively) often accompany trademark names on product packaging and in promotional material, there is no legal requirement to use these symbols, and they should be omitted wherever possible. (If one of these symbols must be used at the end of a product name, it should appear before any period, comma, or other mark of punctuation.) ...
A trademark is a type of intellectual property, specifically a mark used in trade: a business or product name, logo, or slogan.