You might not recognize the name Kelly Blazek, but her story is one that's probably familiar.\nBlazek, the founder of the Cleveland Job Bank for marketing communications professionals, sent a scathing reply to recent graduate and job-seeker Diana Mekota, who contacted Blazek via LinkedIn to ask for advice on searching for a job and to connect via the professional networking site.\nBlazek's reply quickly went viral, and she's become a prime example of what not to do on social media; the story is a cautionary tale about the ubiquitous nature of social media and the power of a viral story. But don't assume you're safe because you're not spewing vitriol or posting drunken selfies -- there are other, more subtle social media mistakes you might be making that could just as easily kill your career.\nMistake 1: Not Keeping Professional and Personal Separate\nThe lines between personal and professional get more and more blurred, and nowhere is this more apparent than on social media, says Chris Duchesne, vice president of Workplace Solutions at Care.com. It's critical to keep all public interaction professional, regardless of which social media site you're on, he says.\n[Related: Social Media Costs -- and Some Workers Are Paying With Their Jobs]\n"It's a good rule of thumb to never post anything you wouldn't want a boss or prospective employer to see," Duchesne says, and always assume that, no matter how strict your privacy settings are, that your post will be seen.\n"People do extensive research on these sites before they hire you," Duchesne says. "Because of the technology, the personal and professional spheres are more integrated than ever, and it's safest to assume that your social media persona is not separate from your professional persona," he says.\nJean Dobey, CEO of social networking site Hibe.com, founded his company specifically to address the separation (or lack thereof) between the personal and professional on social media. Hibe.com allows users to create "micro social networks" that include connections only between contacts and friends from specific areas of your life, he says.\n"As a medium, we looked at social networking and realized we have different 'faces' to interact with different people in different aspects of life," Dobey says. "People should have privacy and the ability to separate those spheres from each other, and while you can do this within existing social platforms, ours takes it to a different level," he says.\nMistake 2: Not Considering Your Audience or Context\nOne of the problems Dobey says Hibe.com attempts to solve is that of context. Many times, even if a user isn't posting offensive or inappropriate content themselves, other users - their friends, family and other connections - can inadvertently undermine their professional reputation online, he says.\nAs an example, Dobey says, imagine you're in a restaurant having lunch with a professional colleague. You're wearing a nice suit, and chatting about professional matters. If a college buddy walks in and sees you, they're able to take in your demeanor and appearance and make an assumption that they should approach you in a professional, reserved manner, since it's obvious you're in a professional context. But online, via social media, it can be difficult to interpret these contextual clues, he says.\n"That can lead to some major misunderstandings and social faux pas," says Dobey. "If you post content in a professional context, but your college buddy can't tell that, he may reply with comments or other media content that's completely inappropriate - and that's bad news for you," he says.\n"You need to really understand who your audience is when you're delivering content online. When that audience is mixing personal and professional, you're going to introduce misunderstandings. The best way to avoid this is to keep them completely separated from each other," Dobey says.\nMistake 3: Beware of Zombie Content\nOne of the most important things to remember about online content in general and content posted to social media in particular is its permanence, says Brandon Metcalf, CEO and co-founder of recruiting software solution Talent Rover. That photo from your college spring break? It's still out there, somewhere. And it may come back to haunt you, he says.\n"You have to be aware of how permanent this medium is. Once content's out there, it's out there forever -- it'll never die, like a zombie, and you should be aware that it'll probably rear its ugly head at the worst possible moment, like when you're trying to get a job," he says.\nOne of the first things recruiters do is Google candidates, and scour social media to get a sense of the candidate's personality and potential cultural fit with an organization, Metcalf says. Echoing Care.com's Duchesne, Metcalf says a good rule of thumb is never post anything on social media that you wouldn't want your mother to see.\nMetcalf says the "incriminating photo" problem happens even to candidates who should know better. In one case, he says, he was recruiting for a major investment firm, and had located the perfect candidate -- the right skills, experience, background and location -- but what he saw on the candidate's Facebook page gave him pause.\n"One thing I always do is scour Facebook for candidates' background and culture information," Metcalf says. "Luckily, I noticed that this candidate's Facebook profile picture included both him and a blow-up doll. It was likely to cost him consideration for this job. I got in touch with him and he quickly changed it, but it's another cautionary tale," he says.\nWhat should you post? Metcalf says when looking for a job, try to focus your content and posts on the industry or area you're trying for.\n[Related: How to Avoid 5 IT Career Missteps]\n"If you're focused on getting a job in, say, investment banking, then share information and comment on happenings in the industry. That way, when a recruiter does see your profile, you instantly have credibility as someone who is interested in and engaged with the industry and major players -- you're branding yourself as a thought leader," he says.\nAnother mistake candidates make, Metcalf says, is appearing desperate in their interactions with hiring companies. Many will continually send and resend LinkedIn requests, or deluge companies' Facebook profile with comments or requests for interviews, and that becomes and instant turn-off, he says.\n"Be respectful, first," he says. "You can certainly send a couple sentences about how and why you want to connect on LinkedIn, or comment a few times on Facebook and express interest, but beyond that you look desperate, and you'll never get a job," he says.\nMistake 4: Unbalanced Online Content\nIf your social networking connections are a mix of the personal and professional, you need to make sure you're not perceived as "partying" more than working, says CEO and co-founder of Strikingly.com David Chen.\nChen's company offers a one-click solution for users to create personal websites that can serve as online resumes or portfolios, and offers integration with LinkedIn to better showcase job-seekers' talents, he says.\n"You're not only being judged by the personal content versus professional content you post, it's also about the ratio of non-work-related posts that show up in your feed," he says. If too many "personal" posts are appearing, you may come across as someone who's not dedicated or serious about your job or professional responsibilities, Chen says.\n"A good rule to follow is this: one third 'interesting content' posts, one third 'informative' posts and one third 'promotional' posts," he says.\nMistake 5: Ill-timed Online Content\nAnother common mistake, Chen says, is the timing of your social media activity. Because most online content is time-stamped, your current or future employer can easily determine if you're regularly posting online content during work hours, and depending on their policies, that can get you fired, he says.\n"Are you blogging or Facebooking during work hours when you shouldn't be? Your boss or a vindictive, catty co-worker can easily catch on, landing you a warning or a meeting with the HR department," Chen says.\nCare.com's Duchesne advises taking your cues from senior leadership in your company to determine when, how much and what type of content is appropriate to post.\nMistake 6: Making a Poor Online First Impression\nThe first impression employers or potential employers have of you now comes from Google and from social media, Chen says. If the first few search results for your name aren't the most flattering, you've got to create new content -- like a personal, branded website -- to replace those results, he says.\n"Monitoring your online professional impression also means checking out what Google Images says about you. Often that's the most incriminating tool for potential and current employees -- because it's the first thing that pops up," Chen says.