She writes columns for The Independent. It's pretty good although, ahem, I've read better.
Hers are about, not to put too fine a point on it, sleeping around. Actually, it's called Sleeping Around, although if they turned it into a TV series starring Billie Piper it'd probably be renamed The Not-So-Secret Diary Of A Writer Who Likes Getting Laid And Then Contextualizing.
It's sort of interesting and funny, although she has a tendency to say stuff like: "Over egg for breakfasts, I sat down to face a woman who knew that I'd slept with both her ex-husband and son".
Yup, well worth tracking it down. Puts Littlejohn's rants to shame.
I'm surprised it's so popular, though. Sex is a bit like drugs or local politics; people who talk about it too much are bores.
But Townsend – a London-based American pushing 40 and, according to her latest column, currently enjoying regular sex with businessman Charles – gets more hits on her offshoot blog than a punchbag.
Her tales of lesbianism, internet dating, affairs with married men and, undoubtedly a highlight, bedding one bloke before moving on to his son have made her a minor celebrity. And she's not the only one.
Secret blogs by Belle de Jour and Girl With A One Track Mind have created, albeit anonymous, stars of their authors.
Their blogs and now books are read worldwide.
For the male it's not so easy. Nobody wants to read about some Yank bedding the most eligible women in London. It'd just be tasteless, lowest common-denominator boasting. It would also make you jealous.
The nearest to a male version is The Game by Neil Strauss. Part novel, part auto-biography, part how-to manual, it's the supposedly true account of one little bald man's mission to become the ultimate seducer – providing plenty of tips for losers like you and me along the way.
Despite not exactly being an enlightened read – it's contention being that every woman is susceptible to pre-planned patterns of behaviour – it's been pretty successful.
That started out as an internet blog, too.
And so in search of inspiration – any inspiration – I stumbled from Townsend to Strauss to de Jour to dozens of other less famous blogs – not all, but often, about sex – by people who aren't famous but who clearly fancy their chances.
My voyage was proof of the adage: To be a writer, as to be an alcoholic, you only need to say you are one. But to be good at either, others must recognise you.
"Why would anyone want to read half this nonsense?" I asked a friend. "They're just wasting 480 words talking about nothing."
She looked at me quizzically, like she looks when she's waiting for my penny to drop.
"Hmm..." she said. "Still, Catherine Townsend's pretty hot, isn't she?"
I nodded.
colin.drury@halifaxcourier.co.uk