The sheer number of women in boating that place it high as a hobby...over keeping up with friends and family is very low.
My liveaboard girlfriend also enjoys the cruising life but barely has much interest in the nut's and bolts of boating other than slightly assisting in docking. No way would she be on any forum other than when I point out something of interest to her.
Sure in the "pure" cruising circles...there's plenty of women with the same captain rating as their sig other...but not from the general boating population...I would say that of all the boaters I know...and I know plenty as I tow them 8 months out of the year.... I would say it's only a couple percent that would be on this or any boating forum as much as the regulars are.
They have better things to do with their time.