A lot can go wrong when it comes to building a business Website. To find out some of the biggest mistakes companies make when redesigning their website--or launching a new one--CIO.com surveyed Web developers, Web designers and customer experience experts We cite the 12 most often problems, as well as how you can fix or prevent them.\n\nMistake No. 1: Forgetting who your audience is. Your senior management team is not the audience for your website. Your customers are. But all too often companies forget this, creating content they like instead of content their customers will like--and click on. "Customers need to feel that you relate to them," says Charlie Claxton, principal and vice president of Creative Strategy at Produxs, a customer experience and design firm. Therefore companies need to "know as much as possible about [their] customers and clients... and deliver a website that accurately and appropriately speaks to [their] audience." Remember, while you may think your website is about you--your products and\/or services--it's really about your customers. Mistake No. 2: Not going mobile. "Approximately 20 percent of all Web traffic is via a mobile device," says Darren Hill, co-founder and CEO of ecommerce provider WebLinc. "If your site forces your customer to fumble through a nonmobile interface, then your customer is likely to leave the site." The solution: make sure you site is optimized to be viewed on mobile devices. If the platform you use does not include this option, there are plenty of inexpensive tools and services that can help you create a mobile version of your website.20 Mobile Trends and Future TechnologiesMistake No. 3: Changing your URLs and not redirecting them. When asked about some of the biggest website mistakes they had encountered, respondents cited this mistake the most often. "During a site rebranding or redesign, companies forget to 301 redirect all of their old pages to the correct new page. This leads to a terrible user experience and it is very bad for search engine optimization (SEO) since the value of those links is not passed to the new URL structure," says Michael Freeman, senior manager of Search at ShoreTel Sky, which specializes in cloud-based phone systems. The solution: "Work with IT before the switch to ensure that all URLs redirect properly to the new site. This is done easily using a tool like Xenu's Link Sleuth. Take a copy of the old XML sitemap and crawl all of those links. Take note of any that do not return a 301."Mistake No. 4: Using jargon, empty marketing terms or clich\u00e9s that don't tell visitors what it is you actually do or sell. "Tell your audience what you do... in simple language," advises Kelly Garrett, the president\/creative director of Ekcetera Marketing and Design. And "don't assume everyone knows who you are and what you do."\n\nMistake No. 5: Stale or static content. "In today's search society, organizations want and need to be found," explains Michael W. Byrnes, Jr., president of Byrnes Consulting, LLC. "The search engines are going to use content as the biggest factor when they rank websites." So you need to frequently add new, relevant, descriptive (i.e., search-engine-optimized) content to your site.Mistake No. 6: Not integrating with social media sites. To be successful in today's social media-driven world, companies need to provide links to their social media channels (e.g., Facebook, Pinterest, Twitter) on their websites, on the Home page as well as on product landing pages (if appropriate). "Whether that is as simple as a Twitter feed, integration with Facebook or a full-blown branded community with functions embedded in the content pages, if a company wants its website paid attention to, it must have social elements," argues Peter Friedman, chairman and CEO of LiveWorld, a user content management company. 10 Social CRM Tools to Help You Keep Tabs on Your CustomersMistake No. 7: Using Flash. "It's hard to believe companies are still using Flash on their websites," says David Millili, CEO of web developer Pegasus Solutions. "Flash can and will negatively affect your chances for sales on a retail site. For one, it won't work on mobile devices, including any Apple mobile products," he points out. "Secondly, content featured in Flash can't be crawled by search engines, meaning you cannot easily search engine optimize Flash sites in the same way you would a Java-created site."Mistake No. 8: Not including an email marketing signup form on your homepage. "Think of all the lost prospects who aren't ready to press 'buy' but liked what you were saying and would eagerly sign up for your sales funnel (i.e., your email marketing newsletter)," but you don't have a sign-up button or form, says Liz Lockard, the owner of Liz Lockard Marketing Consulting. "Email marketing is one of the best marketing channels for ROI--the Direct Marketing Association puts email marketing's ROI for 2011 at $40.56 for every $1 invested." And if you don't have an opt-in\/email marketing signup on your homepage (or on relevant landing pages), you are losing prospective customers and sales. (For companies looking for an email marketing service provider, Lockard recommends Aweber or MailChimp.)Mistake No. 9: Not doing UX (or usability\/customer experience) testing. "Avoiding UX testing is generally a huge mistake," says Michael Beck, senior marketing specialist at OpticsPlanet. "Most companies are concerned with cost, but simply asking a co-worker to conduct a few tasks in the new layout can highlight otherwise inconspicuous [and costly] issues."Mistake No. 10: Not testing the site in multiple browsers and form factors (i.e., mobile devices) before going live. One of "the biggest mistake we've seen, and a mistake we made early on, was to not test our website in all browsers and on different screen sizes," explains Sandip Singh, the CEO and founder of crowdfunding website Go Get Funding. "Sometimes things simply don't work in some browsers or the layout might break." That's why Singh recommends that all companies view their website on multiple browsers (IE9, Firefox, Chrome, Safari) and on various mobile devices (iPad, iPhone, Android) before going live. Mistake No. 11: Taking cybersecurity for granted. "Antivirus software will only get you so far," states Alex Berry, vice president and general manager of Enterprise Services at Neustar, which advises companies about cybersecurity. "Distributed denial-of-service (DDoS) attacks -- targeted, malicious spikes in Web traffic designed to take out a website -- are not only on the rise, they can cripple your sales, lead generation and customer service," he says. Indeed, "according to our recent survey of IT professionals, 67 percent of retailers who had experienced a DDoS attack said the cost of website outages were more than $100,000 per hour -- about $2 million a day." The solution: make sure your operating and antivirus software is kept up to date, constantly monitor your site and have a backup\/disaster recovery plan in place. Mistake No. 12: Not monitoring\/tracking visitor behavior. The best way to find out what works and what doesn't on your website -- i.e., what your customers like and don't like -- is to measure it, using an analytics program. "Measuring and monitoring analytics is the best way to understand user behavior," argues Tim Gray, a content strategist at Blue Fountain Media. "Yet so many business neglect to set up even basic monitoring tools, [even though] Google has an excellent and powerful analytics tool that is free and easy to use and install."Jennifer Lonoff Schiff is a contributor to CIO.com and runs a marketing communications firm focused on helping organizations better interact with their customers, employees, and partners. Follow everything from CIO.com on Twitter @CIOonline, on Facebook, and on Google +.