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Floyd Mayweather Jr. put out yet another Facebook video over the weekend that's drawn more than 3 million views. It's got all the requisite elements of past viral efforts -- soundtrack-worthy music, Mayweather in various stages of exertion at his Las Vegas gym and a declaration that history will be made May 2.

But this time, there's a marketing pitch from the man himself.

"It's no different from how Ali was known as 'The Greatest,'" Mayweather said. "When someone says 'The Best Ever,' the first person I want them to think about is Floyd Mayweather."

It raises an intersting question: Is Mayweather Jr. the best ever? Is he even in that conversation?

Whether by breadth of in-ring acumen or pull of non-ring persona, the brash 38-year-old has hard-sold his signature label to Millennial-aged boxing followers in much the same manner that Ali -- also known as the "Louisville Lip," by the way -- did it with Baby Boomers.

"Floyd's aura is his zero next to his name, but he is the greatest salesman since Ali," Rick Glaser, a boxing business veteran whose professional colleagues have included Larry Holmes, Roy Jones Jr. and Don King, told CBSSports.com. "He's convinced most of society he's the greatest."

Indeed, in the manner recited poems and called rounds were a dead giveaway a half-century ago, if you're a fan in 2015 and you see the letters 'TBE' on the outside, you probably know the product inside.

He talks trash. He posts pictures. He surrounds himself with A-listers.

And though arguments can be made that he's done those things as well or better than any boxer before him, they're not the sorts of things that are going to get him over with the hardcore fight crowd.

To that bunch, having the most lucrative pay-per-views is not the same as facing the best opponents. Mastering social media does not equate with pound-for-pound supremacy. Sharing face time with Justin Bieber will not put your name on the short list of the sport's all-time greats.

"Floyd Mayweather walks around in hats and shirts which read simply, 'TBE,'" Randy Gordon, former editor-in-chief of Ring magazine, told CBSSports.com. "For the under-35 age group, he can, and has, sold it. They have watched him basically breeze unscathed through opponent after opponent.

"His fights are generally one-sided, not two-sided, affairs. But the under-35 age group, or at least the legions of them who believe Mayweather is indeed [the best ever], have not seen those in Mayweather's weight class alone who may well have been able to hand [the best ever] a crushing defeat."

That's not to say Mayweather's resume is without bullet-worthy points.

He's been champion at every weight from 130 to 154 pounds.

Of his 47 career fights, 24 have been with titles on the line -- and he's won them all. And, after the one fight a significant number of people suggested he'd lost -– against Jose Luis Castillo in April 2002 –- he opted for an immediate rematch and earned a more agreed-upon verdict eight months later.

His list of foes, though oft-derided, does include Genaro Hernandez (TKO 8) and Diego Corrales (TKO 10) at 130, Castillo at 135 (UD 12 twice), Arturo Gatti at 140 (TKO 6), Zab Judah (UD 12), Ricky Hatton (TKO 10), Juan Manuel Marquez (UD 12), Shane Mosley (UD 12) and Marcos Maidana (UD 12 twice) at 147 and Oscar De La Hoya (SD 12), Miguel Cotto (UD 12) and Saul "Canelo" Alvarez (MD 12) at 154.

And at 38 years old -- by which time Ali was a spent husk of himself -- he's still the best in the world.

But to Glaser and Gordon, that last nugget can't be uttered without immediate qualifiers.

"He's the best of this era," Glaser said.

"But he wouldn't have beaten '80s killers [Thomas] Hearns, [Ray] Leonard and [Roberto] Duran."

Is Floyd Mayweather in the conversation as greatest fighter ever?  (Getty Images)
Is Floyd Mayweather in the conversation as greatest fighter ever? (Getty Images)

Lest the youngsters forget, Hearns won his sixth and final weight class title as a 40-year-old in 1999. Leonard ruled five divisions in a 10-year stretch from 1979 to 1989. Duran held four belts in a 17-year run of championship relevance that spanned from 1972 to 1989. The three men also engaged each other in a violent round-robin that saw Leonard finish at 3-1-1, Hearns at 1-1-1 and Duran at 1-3.

All told, their final combined pro record was 200-24-2, with 143 knockouts.

Which, to Gordon, completely eliminates Mayweather from theirs and others' auras.

"To think the young Thomas Hearns would have ever lost to Mayweather is reaching. The same for the Roberto Duran of June 1980, who would have mauled 'Money' May," he said. "A teenage Wilfred Benitez would have also dazzled and probably beaten TBE. The two Sugar Rays (Leonard and Robinson)? Stop it! Let's not even go there. Aaron Pryor would have also had lil' Floyd covering up all night long, unable to muster any kind of offense. [The best ever]? Only if it stands for 'The Best [in his] Era.'"

And when it comes to May 2, Glaser said, he'll lose more by losing that he'll gain from winning.

"A loss to Manny diminishes anything Floyd has accomplished to be considered great," he said.