I would like to iterate that in essence the only similiarities between "capture the flag" (CTF) and "team fortress" (TF) is the flag.

After that the games part their ways.. this is because CTF has no sense of handicap everyone is equal in speed and strength (weaponwise). TF on the other hand requires more "grey matter" i.e. thinking because of the different traits of each character; the scout can outrun every other class of character but is prone to dying very quick from a few shots of the shotgun. All characters have a certain strength the only average character being the soldier.

Because of these interesting twists the game is no longer a case of storm up and meeting your exact equals (traitwise) on the other end. When this happens in CTF it comes down to who is the most skilled in "Close Quarters Combat". In TF one could send a scout to retrieve the flag, who enter the opposition's fortress and be met by not regular characters but infact sentry guns. Now you're piting the cunning of a Engineer against the speed of the Scout.

TF has also spawned mini games (much like Quake did with it's mods); one that I vividly recall is called "Sniper Wars" in which the entire game is based around the Sniper class.

As with all micro culture TF also has guilds for each class of character. One can hone their skills at being a demo man or get the magic one shot kill of the sniper.

In conclusion with all these facts I find it difficult to merely class TF has being just based on CTF, it's far more...