Your sorcery affects the world in a very fundamental way, and this does not stop at the effects you produce consciously. Strange effects occur around you constantly, either as a result of your rampant subconscious use of magic, or simply as a form of backlash from a reality that you can twist to your whim.
Echoes are spontaneous manifestations of power outside of your control. They are noticeable, and can give people in the know information they would not otherwise have. They can also be direct hindrances; when your car suddenly turns into a giant barrel, you are up shit creek.
Echoes act to ruin your day. They are never helpful. Whatever force is behind the echoes knows all you secrets, and sometimes lets on things that even you do not know. The echoes often act to show you something, to really rub it in, such as when every number you read during a day is the exact amount you shortchanged that waiter.
Echoes are rarely directly dangerous, but the do become more intense as you use more of your magic; if you start to strut your stuff too much, echoes get outright nasty. Echoes also get more power when you spend Magic points. They can be very powerful, much more powerful than your sorcery. They do grow in power as you grow in power, always staying a bit ahead.
Echoes are generally funny, in a sadistic kind of way; they never obstruct the story, but can create setbacks and hindrances for you and (rarely) your friends. They are a great plot device for the GM to use when you are taking too much camera time or are using your magic for tasks that really demand role-playing.
You can suggest echoes, or your game master can invent them. If you invent funny and annoying echoes, the game master will probably go easy on you with his own. In either case, it is the game master that has the final word on what happens.