Let me get one thing straight immediately. Progressive's 100th ad featuring Flo does not merit four stars all by its lonesome. In fact, as a stand-alone ad it almost fails entirely. Sure, it's funny in an Eddie Murphy or Mel Brooks or Martin Lawrence sort of way. But if you were coming to it cold, you'd be hard-pressed to tell me what it's supposed to be selling.

The thing is, you're not coming to it cold. If you're like me, you're coming to it with years of goodwill -- or at the least, years of cultural awareness of Flo -- so let Flo and the actress who plays her (Stephanie Courtney) have a good time. Let Flo's fans learn just a little bit more about where Flo's coming from.

The fact of the matter is, Flo is now part of the American cultural fabric, and I don't have to explain what Progressive is.

Prior to 2005, if I'd written that a car-insurance spokescharacter was a recognizable part of the American cultural fabric, you wouldn't have let me behind the wheel of a car. But at the dawn of the new century, Geico, using a pile of Warren Buffett's cash, shook up the insurance-marketing category with a saturation effort featuring numerous campaigns. Progressive followed with Flo in 2008. Their efforts sparked a dormant corner of the marketing world into a $4 billion-a-year ad inferno.

Insurance giants Allstate and State Farm not only took notice, they had to play catch-up. In 2011, when talking about the new "Mayhem" campaign, one Allstate exec got right to the point. "We wanted to kick Flo's ass." That speaks to the power of Flo as a marketing tool. That and market share. Progressive had 4.9% of the auto-insurance market in 1999. In 2012, its market share was 8.3%, according to the National Association of Insurance Commissioners.

Like a lot of powerful -- and popular -- advertising characters, Flo can be polarizing. A quick Google search will turn up "I Hate Flo" groups on Facebook and even a blog post titled "Flo the Progressive Insurance Lady and Why She Should Die," written by someone who's got both grammar and anger issues.

But I like Flo. And so do millions of Americans.

Of course, with a campaign this old, the marketer might be tempted to experiment or ditch it. Indeed, Progressive has rolled out a Flo-less corporate campaign, a talking spokesbox and "The Messenger," a somewhat creepy drifter of whom the less said, the better. But Progressive's marketing execs aren't stupid. During each one of those other efforts they made it clear that Flo wasn't going anywhere.

Besides, marketers -- and viewers -- can walk and chew gum at the same time. Geico's Gecko can do his thing while the company cycles through googly-eyed stacks of cash and banjo players and exuberant camels and cavemen. (Fun fact: Stephanie Courtney played the HR woman in the short-lived ABC comedy "Cavemen," which was based on one of Geico's first big ad hits.)

And while Progressive considers its next move, the real Flo can keep doing what she does best -- charming some of us, annoying the hell out of others of us and making Progressive an instantly recognizable household name. I, for one, am more than happy to meet Flo's family in this, her 100th, spot.

Advertising that a viewer looks forward to? That deserves four stars.