This term is generally used following a direct quotation from another poster. Acronyms are popularly used on the Internet to cut down the amount of typing necessary to communicate. On web forums, where long posts are often made in heated debates, a simple QFT indicates what "side" the user is on. This allows readers to filter through the thread more quickly.
A QFT is seen as a compliment to the original poster, but also decreases redundancy on a board. Rather than making the same arguments over and over again, posters can simply quote what has already been said, an option available on most forums, and indicate that they support what has already been said with a QFT.
QFT (2)
Acronym form of:
1. quoted: past tense of coten from M.E. 'to mark a book with numbers or marginal references'
2. for: to indicate purpose
3. truth: from M.E. trewthe 'loyalty'