Letters are important means of communicating both personal and business sentiments. However, personal letters are vastly different from their business counterparts. To show proper business etiquette during your company transactions, you should recognize these differences and take pains not to mix letter styles. This will help you look professional to employees, clients, shareholders and investors.
Business letters and personal letters are formatted much differently. With some minor variations, business letters usually have 1-inch margins. They also have single spacing, with double spacing only between paragraphs and introductory data lines (e.g., date, subject). The letter is left justified with no paragraph indentation. Business letters also are always typed. By contrast, personal letters can have virtually any format. It is up to the writer to decide how he wants the personal letter to appear. A personal letter traditionally is handwritten, but with technology advancing, many people type personal letters on their computers because it's faster to type than write manually.
In a business letter, content is always objective-oriented -- that is, the purpose of the letter is transparent. With a personal letter, content can cover many different topics, and there is more of an emphasis on relating past events and emotions than on problem solving. Personal letters can be much more meandering. Personal letters may touch on some business or finance issues, but business letters never discuss personal issues unless those issues directly impact the business.
Business letters use more formal language than personal letters. Writers pay special attention to word choice because word choice can make a huge difference in legal matters. Salutations and closings are polite and refer to proper titles (e.g., Chairman Edwards, Miss Neman). Colons are used more in business letters than personal letters, particularly after the salutation and the introductory data line labels (e.g. RE:, DATE:). Personal letters can use any language, including slang and non-business abbreviations like ttyl (talk to you later) or btw (by the way). The advantage to this is that the personality of the writer truly comes across. Business letters often lose the writer's true "voice." Personal letters use standard punctuation rules, but because they are so informal, writers often ignore some basic punctuation and capitalization standards.
The main reason why people separate personal letters from business letters is because a standard method of writing a business letter creates efficiency in business operations. For example, businesspeople know they quickly can ascertain the purpose of the business letter from the subject line. Efficiency can translate into revenue. Another reason for differentiation is that using a professional format conveys that whatever is in the letter is of importance. Third, the use of business letter format is expected by professionals. If you do not adhere to business format with your company, you may come across as less prepared or inexperienced.