It's not what other people think of you that matters. It's what they can find out about you on the Web that will affect your ability to get a job or promotion, rent an apartment, buy a house,
Increasingly, your personal reputation is at the mercy of search engines, blogs, and social networks, none of which themselves have a sterling reputation for accuracy.
Identity theft, libel, defamation, mistaken identity, and youthful indiscretions captured forever--these are just a few of the things that can come back to bite you.
Fortunately there are ways to fight back--five ways, in fact. And it all starts with discovering the depth and breadth of your personal Net footprint.
1. Google Yourself
"Google is no longer just a search engine; it's a reputation engine," says Chris Dellarocas, a professor at the University of Maryland who studies online reputations. The first step in taming this beast is to find out what's out there by Googling all variants of your name, your phone number, and your address.
If you've put stuff on your own sites that you don't want Google to find, you can ask the search engine to delete it from its results. If someone else posted this material, though, Google won't remove it. You'll have to ask the site owner to take it down--or hire someone to do it for you (see item #5).
2. Comb the Web 
Start by looking at so-called "people search" engines. Sites like Pipl, Spock, Wink, and ZoomInfo scrape information from other Web sites (like social networks) and slap it together into personal profiles. It's not uncommon for such sites to mix information about different people with the same name and present them as a single person. That's not so good if you've got the same name as, say, a porn star or a disgraced former Congressman.
Spock goes a step beyond; its bot software selectively pulls individual words from your sites and adds them as "tags" to your profile. Taken out of context, some tags can be extremely damaging--as when Spock tagged prominent political blogger John Aravosis as a "pedophile" because he'd written about Congressman Mark Foley. In many cases you can contact the sites and have information removed or corrected (to find out how, locate the site's privacy policy or contacts page). Spock will e-mail you if your profile has been changed, but only if you register with the site.
There are also hundreds of online address books that contain information on you, some of which surely won't be accurate. For $5 a month, Reputation Defender offers a service called MyPrivacy that locates your listings in some of the major Internet white pages and lets you remove your data. At press time, though, the service--a beta--was still buggy and incomplete. (See item #5 for another Reputation Defender service.)
And don't forget Wikipedia. You may have a false or defamatory entry in the world's most popular online encyclopedia and never know it. In the most infamous case, retired journalist John Siegenthaler publicly outed the encyclopedia for a false entry that implied he played a role in the Kennedy assassinations. If you've got a Wiki page and want to keep it, you'll need to keep an eye out for erroneous edits.