Alexa is like a seismograph station for Internet sites.
If you check eHarmony, Match and PlentyOfFish you will see they are high activity level sites.
CupidMedia owns and operates 35+ International online dating sites, no one of them have high activity levels according to Alexa and they are
If you register and begin to use any of those sites, perhaps you will discover the main objective is to attract men and send them to other adult content sites ( check the link, in Alexa, www dot blackcupid dot com www.alexa.com/siteinfo/blackcupid.com and see where it redirects! )
To be more clear, those 35+ online dating sites are only "special purposes vehicles" to redirect men to adult content sites, and most probably 90% of profiles in their databases, are only fake profiles of women designed exclusively to redirect men to adult content sites. No more than that. Quite similar to "AshleyMadison case, sued by ex-worker who claims she wrote too many fake female profiles."