Professional letters require a formal ending phrase in order to have the appropriate tone and voice. There are two types of sign-off phrases that can be used in business writing. The first should be used in a letter delivering positive or neutral information. Some examples are: yours truly, respectfully, sincerely, with many thanks, and regards. Letters of sympathy or containing negative news should be ended with phrases such as "with sympathy," "sincerely yours," and "with condolences."
Letters written to family members and friends require friendly, familiar closing phrases. Using inappropriately formal closings will come across as cold or distant to your reader. When writing to friends or family, good closing phrases include: with love, yours, always yours, all my best, thanks, and see you soon. When writing to older family members or friends, increasing the formality of your closing phrase is appropriate. With friends and family it is also okay to close with a time-sensitive closing such as "happy birthday" or "happy holidays."
Sometimes we write to people we don't know in positions of importance. If you are sending a positive letter to a politician, an ending phrase such as, "your loyal constituent" or "thank you for your work" are appropriate. Negative letters should end with a respectful but neutral phrase, such as sincerely or regards. Letters to celebrities should end in respectful, familiar phrases, such as sincerely yours, or your biggest fan.
The Internet has its own rules and codes of behavior. When writing a business email, professional email, or email to a celebrity, it should be written and ended just like a formal letter. However, when writing to friends, Internet friends, or strangers online, there are different ways to end emails. Instead of sticking to formal phrases, the ending phrase of an email can be anything: "talk to you later," "have a good one," and "seeya" are examples of email closings. Even emails written to strangers online can be signed in an informal way without seeming rude.