Here in the twenty-first century, your most important asset might not be your bank account, your car, or even your home, but rather your reputation. Specifically, your online reputation, the personality and presence you have created on social media networks. When it's possible for people do an online search to find out more about you (more and more common when, say, you're applying to jobs and more than half of would-be employers check your social media profiles before hiring), it becomes increasingly important to make sure that your online persona shows the side of you that you hope to project.
It's also becoming increasingly difficult to keep your online presence entirely under control. Social media sites are ever increasing, allowing your friends, family members and business partners to share new things about you every day. As a result, pictures and stories that you thought had disappeared forever have a tendency to show up with little warning. (If I see one more picture of me on the elementary scholastic scrimmage team…) How can you keep your online persona as pristine and desirable with so many avenues to consider?

Methods to Maintain Your Online Persona
1. Join the Sites: I know, I know, it seems like at least once a year there's a new site that you simply must join to keep your personal image up to date, from Facebook to Linkedin to Twitter to Google+ (Alright, that last one never really caught on, but still, others will be coming). If you hope to get a feel for what your friends and family are saying about you, as well as putting out some positive points yourself, you need to put yourself out there. To find out what other people are putting out there about you, it's also a good idea to:
2. Google Yourself and Correct Any Falsehoods: Let's be honest, you've probably done this already; here's my search, for example. But whether you have already or not, you should be sure to check the things that are already floating out there about you, to see what, if anything, there is about yourself that you need to tweak, alter, or just plain eliminate in the near future. It's an important matter to make sure that you keep the information out there about yourself as accurate, and ideally positive, as possible.
How you can do so can be a tricky matter, depending on what the information is, the site where it is located, and who is running that site. Usually, you can contact the site owner and let them know that there is incorrect information posted (the bad info about you is wrong, right?), and get them to take it down. Sometimes, you might need to look into other means to get the information removed, from taking advantage of the policies of the hosting site(s) to using legal means. Hopefully it won't come to that, but if you need to get truly damaging information removed, you should keep it in mind.
3. Buy Your Websites: Not that you need to be vain or anything, but you should definitely put down a few bucks to buy the websites that correspond to your name. Having [yourname].com will help to ensure that the first thing people notice when they inevitably start to look into your past is what you want them to see. Although, with the large (and increasing) number of domains out there, you'll have to worry about not only [yourname].com, but also [yourname].org, [yourname].info, [yourname].net, and as many others as you think people are likely to visit.
As to what to do when you have all these sites…Well, there are quite a few options. You can leave them empty, and simply buy the sites to keep anyone else from having them and using them as a means to disparage or malign you. You could forward the website to your Facebook page or other social site that you want people to see when searching for you. If you're exceptionally diligent, you could start a blog or another website of your own, sharing positive information with people who search for you, depending on the type of website you create, maybe make a little money on the side.
4. Promote Yourself (Reasonably): One of the major reasons to go to all this trouble is to make sure that people have a positive view of you when they do some searching. But you can't wait for people to just come to you; sometimes (most of the time, in fact) you need to steer them toward the media sites you want them to see about you. There's a lot of ways to do so, thanks in no small part to all the aforementioned social media sites.
Keep in mind that if you do, though, that you need to do so in a reasonable manner, doing your best to keep something of a gap between your business and personal life online. If you spend all your time on a personal page making comments about your work and promoting yourself, you'll drive your friends and family crazy. At the same time, should you make too many comments about your latest dinner or your cats on a blog or website that is theoretically for business, you're not going to get many clients. Make sure to keep each part of your life in the appropriate place, and keep the cross-over to a minimum. Also, make sure to:
5. Watch What You Say: There's a temptation to treat social media sites a lot like your home, a place where you can let down your hair and behave however you want. Instead, it's important to remember that everything you say and do will be recorded and easily accessed by anyone wanting to learn more about you. There are limits on what you can say without your bosses being able to, well, fire your ass, just as an example. There are also some methods for you defend yourself from being canned, depending on exactly what you say. (Take advantage of the protection of employee's rights to association and union representation as defended by the National Labor Relations Board seems to be one of the best ways to go.)
Still, rather than rely on those rules and exceptions, it's better to watch what you write in the first place. If you watch what you (and anyone claiming to be you, hence to need to check to see what comes up when you do a search) say, you'll be in much better shape and can avoid those sorts of troubles in the first place.