I'm trying to decide if I find it ironic or troubling that the first item to pop up when I searched for "Colossians 2:8" to get today's verse was an ad for Mormonism - an empty tradition of men that leads people from Christ! From Paul's day to modern times believers have been assailed with traditions and philosophies that were either totally contrary to the gospel or added other beliefs or works needed to attain true salvation.
The Greek for "captive" (sulagogeo) meant to carry off booty, to carry one off as a captive or slave, or to lead away from the truth and subject to one's sway. Satan intends to keep people from true faith. If he cannot keep you from faith in Christ, he will try to lead you away into a focus on good works or a focus on false teachings rather than on Holy Scripture. Every day of your life is a spiritual battle, and you must put on the armor of God and be alert for the one who comes to steal, kill, and destroy. From Genesis 3 until modern times Satan's power is deception, subtly or grossly distorting the truth to lead people away from God.
The NLT translates this passage as warning against "empty philosophies and high-sounding nonsense". Although others may speak high sounding words that seem to be logical or may be more able to clearly articulate their position do not be carried away! Become so fully grounded in Scripture that you can immediately recognize false teaching for the poison it is, no matter how good it may seem or how closely it resembles The Truth.
Be on your guard lest some one take you as a captive slave away from the treasure of the kingdom of God!
Let no one deceive you with empty words, for because of these things the wrath of God comes upon the sons of disobedience. - Ephesians 5:6