By now, the perils of securing online data with little more than user names and passwords should be well known. Monster.com learned that lesson late and the hard way, prompting this week’s disclosure that the Web jobs board will spend millions of dollars to improve its security.

Monster Worldwide Inc. recently discovered that con artists had grabbed contact information from resumes for 1.3 million people — and likely many more, since Monster now says this was not an isolated incident. Files were pilfered not only from Monster.com but from USAJobs.gov, the federal-government career-listing service operated by Monster.