If you are writing within an environment that you feel comfortable using Internet slang, such as your personal Facebook page or a character-limited service such as text messaging or Twitter, by all means utilize the abbreviation. If you are writing on a more professional stage, such as within a business email or on your LinkedIn account, you would be better off choosing another way to express that this is your opinion, as the abbreviation may be seen as unprofessional and the full definition is often unnecessary. In most cases, simply stating your opinion without the lead-in is not only more concise, but also more effective.