When it comes to customer service on Twitter, companies and brands need to be on their game. A single critical tweet from one person (depending on who that person is and the nature of their complaint) could lead to a PR disaster. After all, anyone can view tweets and start to view a company or brand in a negative way, depending on what is being said about them.

A new study carried out by TOA Technologies shows that more that 1 million people read customer service-related tweets every week. More than 80 percent of those tweets are of a negative or critical nature. The study examined more than 2,000 tweets between February and May, with a focus on Twitter users’ perception of the cable installation service industry. It did this by targeting tweets that contained terms such as “the cable guy” and “installation appointments.”

TOA found that 82 percent of the tweets had a negative sentiment, and that these tweets reached 780,000 followers before any retweets came into play — so many more people are likely to have seen these negative tweets. It should be noted that this was a small scale study of tweets related to a single industry (and a small one when compared to airlines, for instance).

I’m not sure that TOA found the most representative industry to carry out its study on — most people don’t like to wait for the cable guy, who can show up at any time in a 4- or 5-hour window, and that may skew the results. However, the study certainly provides some indication as to the problems facing brands and companies on Twitter.

Customers of a company or brand who have a negative customer experience can act as influencers, as they might tweet about their bad experience to their followers. Considering that some Twitter users have more than 10 million followers (ok, it’s not likely that Lady Gaga would complain about a company on Twitter, but bear with me), there are a lot of people who could change their view of a company if someone sends a negative tweet.

What this means is that companies and brands really need to be paying attention to what is being said about them on Twitter, so they can respond quickly and try to resolve any situation. However, it might not help matters much if an ill-judged tweet is sent out from the brand’s own Twitter account.