Corporate blogs have gone through some growing pains.

Chief executives and their employees have used pseudonyms to attack critics or defend their company on forums. Companies have created blogs meant to look like they were started by fans of their products.

The highest-profile case of a CEO-blogging faux pas involved Whole Foods Chief Executive John Mackey.

Mackey was exposed by the Wall Street Journal last summer for using a pseudonym to post anonymously for eight years on a Yahoo Finance forum, in which he cheered Whole Foods and critiqued his competitor Wild Oats, which Whole Foods ended up acquiring.

Mackey tried to defend himself on his company blog after he was outed, but ended his blogging when his board told him to stop while the Federal Trade Commission considered the pending purchase.

Mackey resumed blogging last month, saying he made a mistake in judgment but defending his right to express his opinion.

Also last month, two Burger King employees were fired for participating in unauthorized activities on public Web sites that the company said did not reflect the company's views and violated company policy.

Burger King did not identify the employees.

According to an Associated Press report about the firings, a Burger King executive used his middle-school-age daughter's screen name to attack a migrant-worker-rights organization with
which Burger King had a dispute about farm worker wages.

Burger King also stopped using a security firm whose employees were posing as students interested in helping out in order to gain access to the workers-rights group.

Another corporate blog blunder involves what's called a ''flog,'' or a fake blog. It typically involves a company helping to create a blog that appears to be written by an individual who is enthusiastic about the company's products.

High-profile flogs in the past have involved Coca-Cola, which used a blog to promote Coke Zero, and Wal-Mart. Wal-Mart's public relations firm paid a couple who were traveling across the country in an RV and spending each night in a Wal-Mart parking lot. The couple then wrote about happy Wal-Mart employees on their blog.

But the most common blunders involving chief executive bloggers are not scandals. They involve using ghost writers without revealing it or writing infrequently, says blogging consultant Debbie Weil.

''It usually isn't saying something inappropriate,'' added Weil, a corporate blogger and social media expert. ''Most of these people are media trained. It's that they're perfectionists. They want to do something so well, they don't understand that it can just be a short comment.''