Plentyoffish dating forums are a place to meet singles and get dating advice or share dating experiences etc. Hopefully you will all have fun meeting singles and try out this online dating thing... Remember that we are the largest free online dating service, so you will never have to pay a dime to meet your soulmate.
My only message restrictions (when actually using this site for more than forums or not) are the "intimate encounters" restrictions since I don't want to unknowingly end up grouped in with them by exchanging harmless emails. Everyone else is free to message me because I've exchanged messages with forum members. I'm still quite selective when it comes to dating, I assure you. Just because I don't have "must not smoke" as a restriction doesn't mean jack squat; I'll never date someone who smokes! That's something I can filter out after a message has been received, if the intention is dating.
When I used POF for dating, I never had any email restrictions. Sometimes a person that is just outside my preferred age limit could be a good match. But wouldn't be able to email me if I had age restrictions. Email restrictions won't necessarily prevent married people or drug users or other "undesirables" from contacting you. A lot of people would lie about these things on their profile. Email restrictions might be more effective for people who get dozens of emails per day. But that never applied to me.