“It takes many good deeds to build a good reputation, and only one bad one to lose it.”

Your reputation – and your online credibility – are as fragile today as when Benjamin Franklin wrote those words in the 18th century. You carefully construct your authority brick by accurate brick. A little crumbly mortar can make the whole thing collapse.

Credibility is especially critical for lawyers whose careers are built on their ability to provide clients with sound legal advice – and provide courts with watertight legal arguments. One factual error can call into question everything else you’ve written.

My dealings with car salespeople over the years have highlighted the importance of knowing what you’re talking about. I’m a bit of an auto enthusiast. When a salesperson tells me something I know to be factually incorrect about the vehicle I’m looking at, doubts arise about the whole transaction and the salesperson’s overall competence.

This issue is much more serious in the legal profession, where a client’s financial future often hangs in the balance.

Whether it’s a book, an article, a blog item, website content, a Facebook post or any other written material, the presence of one factual flaw can call into question the accuracy of everything else. If I spot a particular fact that is verifiably wrong, how can I trust what the author has to say about the (many) things I don’t already know?

Don’t think it can happen in the legal world? It can and it does.

As a Web content editor, I read reams of writing about legal issues. Much of it is thorough and accurate. Some of it is downright wrong and borderline amusing.

Below are a few examples. I’ve changed identifying details to protect the guilty.

• “If you’ve recently been injured or fallen ill due to a work-related incident, you are eligible for certain benefits under Constitutional law.” (I am curious which article or amendment to the Constitution guarantees workers’ compensation benefits.)

• “Hawaii is one of the most popular tourist destinations in the continental United States.” (Continental drift must have really accelerated if the Aloha State is now part of the 48 contiguous states.)

• “Workers’ compensation insurance paid a total of $1,403,986 for injured workers’ medical bills in Michigan during 2013.” (Health care must be cheap in Michigan if the total bill for a year’s worth of medical treatment for every worker’s comp claimant totals less than $1.5 million.)

• “If approved for appeal, a commissioner will assess your case record and provide concise, legally supported judgments based on statutory case law.” (This jurisdiction must be the first in the nation to codify its common law rulings.)

• “Under Arizona DUI law, you may be convicted of a misdemeanor if you are either driving under the influence of alcohol, which is sometimes called “generic DUI,” or are driving with a blood alcohol level (BAC) of 0.8 percent or higher.” (Someone with a BAC of 0.8 percent would likely die of alcohol poisoning. The statute actually reads 0.08 percent – off by a factor of 10.)

To be fair, many of these errors may have been the result of a typo or a momentary lapse of mindfulness. Whatever the cause, the result is the same – serious damage to the source’s credibility, reputation and authority.

Keep in mind that most readers of your blog posts, tweets and other online content assume that you, the attorney, wrote it yourself. Your readership includes not only the clients who pay your fees, but also your colleagues at the bar and on the bench.

To protect the good name you have worked tirelessly to build, it is crucial that your legal Web marketing partner has the same eye for detail and accuracy that you do.