This answer varies with other sites, so i won't speak to those. But as far as my experience with OKCUPID (fifteen years). They answer is yes they do. Not EVERYONE is hunting for a spouse. The current options on OKC are: Hookups, New Friends, Short Term, Long Term. You also can selected if you prefer monogamy or ethical non-monogamy.

(There are a LOT of men and women that understand that monogamy is a failed paradigm to expect everyone to adhere to, its not one size fits all. If it was, there would be very few cheaters.)

I have found what people select (casual, short term, long term) doesnt really matter. Relationships will naturally seek their logical state. If you meet a girl looking for a hookup and you both have OMFG chemistry, why would you never call her again?

That actually happened to me. I met a younger woman stating she ONLY was interested in a summer fling because she would be returning to college in September. It started as casual sex in July, but when when September came we wanted to continue seeing each other. And in the Spring we both realized we had fallen in love almost instantly, we were holding back because we were trying to enforce the HOOKUP paradigm.

Most women (and i assume men?) that think they want monogamy will state that in their profile and will ask you your intentions when you start chatting. If you say anything other than "i am monogamous and am only interested in serious relationships" they will tell you goodbye.

This is coercion. You have to agree to a committed monogamous relationship with a total stranger... BEFORE YOU EVEN MEET. Take a moment and forget how you have been programmed by society and read the last sentence again and ask yourself if that seems reasonable. But if everyone is demanding it, then everyone thinks its normal and reasonable. I was 40 before i discovered that there are "normal" people that understand humans are not inherently monogamous, society and religion force it upon us and shame us if we aren't in compliance.

What happens is that lying, cheating, and betrayal have become normalized, whereas honesty and authenticity are punished.

But to answer your question, on OKCUPID there are decent, attractive, fun, intelligent quality people seeking casual and long term relationships. Be honest in your profile and say that you are honest and value honesty in others, even if the truth isnt convenient. Don't say long term if you really want casual, there are other people also looking for casual.

Yes. They'll never meet with you because they're contractors and 3rd party representatives, which is a fancy term for scam artists contacting you and pretending to be someone you think that you're looking at in the picture/profile that you are in contact with. The photos are ripped off from Facebook, Tumbler, or porn websites. THESE ARE THIEVES! I was robbed for over 150$ by one of these sites, and it's time to let everyone know. MAKE SURE THAT YOU READ ALL REVIEWS BEFORE REGISTERING FOR ANYTHING!

No site I have investigated has in place any means to purge scammers. At least that they actively employ. SO ALWAYS BE CAUTIOUS.

The people who engage you in conversation but want to avoid meeting in person are usually paid by the site to drum up traffic. They use stock photos of models to attract your attention, then exchange messages with you. At least 50% of all the female profiles on any of these sites are fake. When the real numbers on the Ashley Madison site were revealed, it was found that there was 1 actual female user on the site for every 2350 male users. On sites like Match.com and OkCupid the ratio is closer to 1 female user for every 19 male users.