Twitter is the canary in the coal mine of public opinion -- for celebrities, politicians, and, of course, corporations. When European discount carrier Ryanair lashed out at "lunatic bloggers" after a Web designer reported a glitch on the airline's site, its online reputation dipped as low as its fares. Conversely, Mars got a sweet treat when it posted Skittles-related tweets on its Web site, learning immediately how people felt about the candy.
Twitter's explosion from microblogging curiosity to mass-media phenomenon  has awakened a lot of companies to just how fast memes spread on the Internet today. Make a mistake like Ryanair's -- or Johnson & Johnson's offensive Motrin ads last winter -- and the response is brutal. Get it right like shoe retailer Zappos and bask in the love. How can you know if your canary is singing or dead? These tools will help you monitor not just Twitter but everywhere the online conversation involves your brand.
TweetDeck . To follow the raging tweetstream, you need a dashboard. This free download splits your Twitter feed into subgroups, letting you follow shout-outs (@replies) in one window and specific searches in other views. For instance, Pepsi could follow Mountain Dew, Gatorade, Tropicana, and Frito-Lay in four different search fields, receiving instant feedback on announcements and ad campaigns.
Scout Labs . Need to monitor feedback on your new product? Scout Labs reads blog posts and social-networking comments from around the globe and judges them by their words and tone. The sentence "I love Amazon but the Kindle 2 is disappointing" gets properly parsed as a positive comment for Amazon but a negative one for its e-reader. This ultra-targeted approach allows clients such as Charles Schwab, HP, and Netflix to follow comments in real time and react quickly. Pricing starts at $99 a month for five searches.
BlogPulse . This free feature from Nielsen Online searches the blogosphere for what's happening with your brands. Type in a few keywords and track the number of mentions over the past six months, and view them in a handy fever chart. You can also trace the roots of a Web conversation and learn more about key Web influencers.
Vanno . It's Digg for reputation. Readers vote on news stories, opinion, and gossip about more than 5,800 companies, and Vanno mashes it up into a numerical score. The free site tracks these companies based on 25 topics, including job satisfaction, customer service, and social responsibility. At press time, Cisco was No. 1.
CoTweet . This free service (currently in limited beta) allows multiple people to tweet from the same user name, using software to replicate the success of Zappos's hundreds of staff bloggers, including CEO Tony Hsieh, within one account. Employees can delegate tasks, track conversations, schedule posts, and best of all, identify the people behind the brand.
TNS Cymfony . If you need a more heavyweight tool (starting at $40,000 a year), TNS Cymfony goes beyond simple keyword analysis across the Web and analyzes grammar. It also includes crisis PR solutions that track key bloggers, journalists, and consumers. (Nielsen Online's Buzzmetrics  service offers similar features.) During the past Super Bowl, TNS Cymfony reported that the teaser for the anticipated summer hit Transformers: Revenge of the Fallen earned seven times the buzz of the average ad during the big game.
Use these seven tools and you won't have to worry about revenge; your brand will be transformed into an agile, respected member of the Web's social swirl.