Today, people are using internet far more than they used to just one year ago. The number of users was growing exponentially and is still growing. Unfortunately, people often use internet for wrong purposes and one of them is also reputation attacks on other people. Because people consider internet as a private and anonymous thing, they think that they can write anything they want without even considering the damage that can be caused to other people. The fact that the statement wasn't true is not important at all, because the damage is already done. In order to get your reputation back, you need to react on online attacks.
First of all, you may want to respond to accusations and explain your side of the story. In case the person who wrote defamatory remarks is reasonable, he/she will try to understand it and raise the level of communication. But, in case this person does not understand it, most lawyers will suggest injunction.
Injunction can be very powerful in case it's used correctly. Most defamatory cases are solved with just the threat of injunction, because people are scared of the costs connected to it. The most important thing you need to keep in mind is to seek it against the correct person. Most effective injunctions are sought against the owners of the websites where the defamatory content is published. In addition to the individual writer, an injunction can also be sought against internet service provider.
On the other hand, injunction against unscrupulous people isn't successful in many cases. People who consider themselves they have nothing to lose, are often even more aggressive with writing defamatory content after they receive a mere threat of injunction.
The most important thing we can do about keeping our online reputation is prevention. Treat your clients well, don't give them reasons to hate you and write nasty things about you. In case someone still writes defamatory content about you, you might find out that your other clients are responding (writing comments, blog posts) with their positive experience. In this case, your reputation will even increase.