'Hard-bodied transgressor': Madonna shows her muscle at Live Earth. Photograph: Anthony Harvey/AP
Ever noticed how females of minimal talent but overweening ambition have lately adopted the word "businesswoman" as a defensive job description? As in, "I'm not just the owner of a bosom so freakishly large that people pay to take pictures of it - I'm a businesswoman." But there are businesswomen and businesswomen. Sure, you can pretend that making a million bucks from your body qualifies you for the title, but even the most successful in this league, Jordan and Jodie Marsh, are complete novices next to the greatest businesswoman of them all, Madge Richie (née Ciccone).
Madonna's stock in trade since 1983 has been turning straw into gold, for which hats off to her. And now she's pulled off what could be her greatest triumph yet. Last week she announced that she's leaving her label of 24 years, Warner, to sign a $120m deal with the American concert promoter Live Nation. The company is paying for the right to release her next three albums and back her tours, but you don't have to be Madonna to realise that one of the parties is likely to do far better out of the deal than the other.
Wasn't Live Nation put on its guard by other companies' reputedly failing to recoup on similar massive agreements, such as EMI's £80m contract with Robbie Williams, Warner's $80m deal with REM, and the wad Virgin handed to Janet Jackson in the mid-90s? That's the great irony - by the time a pop star is in a position to command eight- or nine-figure deals, they're generally past their prime, and labels are left with an expensive reminder that Joe Public is a fickle guy.
So how did Madonna do it? She's persuaded Live Nation to take on an act whose albums no longer sell in the numbers they did, and who's bound to scale down her touring due to age and the exigencies of raising three young children. Warner, the label that nurtured her and even gave her the Maverick vanity imprint (to which we owe Alanis Morissette), was offered first refusal and opted not to equal the Live Nation offer. Do they know something LN doesn't? Anyway, Big M must be laughing all the way to the bank.
Despite recovering from the critical and sales flop of 2003's American Life album with the well-received Confessions on a Dancefloor, she will probably never again scale the 15m selling heights of albums like The Immaculate Collection. Then there's her other main business, touring. There's nothing to stop her going on the road into her dotage, a la the Rolling Stones, but her shows are dependent on high-energy choreography and peak fitness, something that will be harder to pull off as time goes on. She can probably guarantee a show full of spectacular stunts no matter what her age, but will the Madonna persona - the hard-bodied transgressor of sexual boundaries - still fly when she's 60? And will audiences still shell out the equivalent of a week's wages to see her?
She'll be up against the same challenge that Mick Jagger faces today: converting a stage act based on relentless physicality into something that accommodates the fact that she'll want to sit down occasionally. Jagger's solution has been to intersperse fits of jogging around the stage with longer periods of standing still. Madonna could always hone the guitar-playing skills she exhibited on last year's Confessions tour, or give an acoustic show a whirl - but can the empress of reinvention reinvent herself as a musician? I wouldn't mind being a fly on the wall at Live Nation right now.