FTP
FTP in a packet stands for "for ten points." It can be placed anywhere in the last sentence where an adverb can go, according to flow considerations. The main significance of FTP is to mark the beginning of a giveaway in the opinion of the question writer. It serves no other purpose in ACF, because everyone ought to know how much tossups are worth in modern quizbowl. In NAQT play or other formats with "blind powers", the FTP is the latest point in the question where the power mark can possibly be (though this rule is sometimes broken, e.g. in the Westbrook Experiment). In the PACE NSC format, stretch round tossups are always worth a 20 point power before or during FTP, and 10 points after.
In NAQT and ACF, a buzz before the FTP signals a good (or at least decent) buzz. In CBI, such a buzz is often impossible, because nothing before the FTP is real or worthwhile knowledge.
Other Acronyms
FTPE - "For Ten Points Each"
FTSNOP - "For The Stated Number Of Points"
Elsewhere
In the British language, FTP is pronounced "Starter for 10."