In a recent Wall Street Journal article, writer Elizabeth Garone covered 5 mistakes people make when searching the Web for a career opportunity. Although job search Web sites as well a social media networks (especially LinkedIn) can be extremely beneficial and often work for many job hunters; however, there are certain mistakes you can make that could be responsible for losing a position, which otherwise would have been perfect for you.

So next time you’re online job hunting, avoid these 5 mistakes that could lose a great opportunity for you:

1. Getting too personal: If you have a Twitter account or write a blog, you need to remember that everything you say and do on those online outlets can be read by anyone, including hiring managers and executive recruiters. According to the article, a study by Microsoft Corporation held in December of 2009 found that 79% of hiring managers and recruiters read online information about job applicants before making the decision to hire. Seventy percent of those hiring managers or recruiters stated that they have rejected candidates based on the online information they found. Bottom line, don’t assume that just because you have privacy settings that your potential future employers aren’t reading what you’re posting. Everything is indexed on Google and can be found through search. To be safe, don’t post anything online that you wouldn’t want your employer to see, because there’s a good chance that he or she might be reading it.

2. Not completing online profiles: Just being on LinkedIn, Facebook and Twitter is not enough to say you are trying to connect with employers through social networks. When you create a LinkedIn account or any other social networking account, make sure to complete all of the information on your profile. Having a lot of half-done profiles leaves a bad impression on employers and executive recruiters who are trying to find out more information about you. Instead, pick two or three social networks and spend time putting effort into building those profiles. Once you have your profile completed, don’t forget to interact on your social network. Join groups and participate in group discussions, make valuable and relevant connections and post things about yourself that make you more appealing to hiring managers, rather than complaining on Twitter about your current job that you hate. According to Garone’s article, members with complete profiles on LinkedIn are 40 times more likely to receive opportunities through the network.

3. Being too quiet about your search: When searching the Web for career opportunities, it’s important to make it known that you are searching. If you don’t update your LinkedIn title or Facebook status that you are open for new job opportunities, how will anyone know to approach you?

4. Making irrelevant connections: Remember that when it comes to connections, the rule is quality rather than quantity. On social networks, only add connections that you actually know or you have done business with. An executive recruiter may view your profile and choose to contact one of your connections to find out more information about you. If that connection doesn’t actually know you in real life, it will reflect poorly on you. When making a connection on LinkedIn, always write a custom introduction explaining to the person why you would like the connect. There’s no excuse for using the generic “I’d like to add you to my network,” that LinkedIn provides because it sends the wrong message and indicates laziness to the person you are connecting with.

5. Only searching online: Given the current economic state of our country and the amount of lay-offs that have occurred over the past few years, many hiring managers have been bombarded with hundreds of applications each time a position opens. For this reason, many companies have stopped posting open positions to job boards, and sometimes even to their company homepage. For this reason, it’s important to engage in person-to-person networking, especially for higher-level positions. Person-to-person networking sometimes may be the only way to find those quality high-level job opportunities, especially because many of them are often filled by executive recruiters. Bottom line, don’t give up traditional job searching and only search online, because you will definitely be missing out on opportunities.

For more information about these 5 mistakes people make when searching the Web for career opportunities, read the full article on WSJ.com.