What do you think is better, a opened RP (that is open to everyone) or a closed RP (that is close to everyone, but open to a few selected people)?

Depends on the scale and what you're doing.

I tend to like open RPs, but I've had some great experiences with invite only games. Normally, I just stick with the tried and true bar of entry to ensure the players are all at a similar skill level and motivation before starting.

I'm only speculating in regards to closed roleplays, as I've never hosted one nor been invited. (aw)

I would say closed roleplays may be fun if everyone knows one another (say a group of friends or long time roleplay pals). However if you don't know one or two of the players and you're invited based on someone recruiting you based on your posts around the site, as well as your tastes, it could be daunting. Someone is picking you and it could put some pressure on you if you feel new or out of your depth. On the other side, if you're a GM and pull certain people together, the pressure is on. Did you pick the right people? Will they stick around and not wander off? I feel like closed roleplays can be littered with mental pitfalls but then again, I'm only speculating here.

My heart lies with open roleplays because it lets me meet new writers and doesn't limit me if someone new joins the site who would be great for the story and I have yet to meet them.

It's that simple for me.

Besides in an open roleplay, you can still invite people to join who might have fun, but with it being open,it still allows for fresh writers to join. Eheh.

Short Answer: It varies too much on RP type and the Players to say.

Long Answer: Note these are generalizations and on average rules and observations being made.

Closed RP's usually only work if people already know each other. If you don't, there's just not enough communication, closeness to collaborate well or motivation to keep going to kepe most RP's alive. Restricting it to select people without allowing a stream of new people spells failure if you can't keep your current group involved, motivated and loyal. Plus, why the hell are you having closed if you're just adding random people you don't know to start with?

So with that being said.

Open RP's are generally the better way, specific people can still be invited but it also brings in new faces and talent you didn't know of before. And these new faces could end up becoming good friends that you'd want to invite to those closed RPs. It also makes it easier to add in new people if old ones leave for some reason.

Closed RP's generally I find only work to be a benefit if you're doing a long/continuous plot line with the same characters, mainly those that have their own separate RP sites dedicated to that group. But even then having new faces can help expand characters, plot lines etc. Hell my first 2 years of forum RP's were on such specialized sites, but in the end over half of our players were new people who wandered in over time. The only other case I can potentially see Closed RP's being a boon is honestly not even a boon but a preference. If you have a specific plot/story in mind and you want to specifically experience it with your friends, kind of like say if you were to set up a D&D group but you only want friends at the table rather than setting it up it strangers.

Both, leaning more towards Closed, personally.

When I first started my rp, I invited a ton of friends and players I thought would be interested in my rp, and I also kept it open for new players to join as well. I found that out of all the people who were in the rp, those who tended to drop first and vanish without a trace were those whom I had never met before, whereas those who stuck with me are the players I invited. Even later on, when we did a recruitment drive for new players, it was open for all to apply as well. Those who became accepted either had to drop, generally didn't understand the plot or concept, or tended to be pretty horrible personality wise that led to conflicts. So there was little joy there.

This isn't to say all the players whom I've invited over the course of the rp have stayed, however they tended to be the ones who've stuck in it the longest, contributed the most, and caused the least amount of drama when choosing to leave. Since my rp is long and plot heavy, I only accept new players on a personal invitational basis, simply because at the stage it's at now, it's so very easy for new players who I'm unfamiliar with to get it wrong, and possibly have a bad attitude with regards to that (and I don't have the patience to experience possible drama like that).

The players who I go out of my way to invite now don't neccessarily have to understand the tone and concept of my rp when joining, or even have the best writing/rping skill, etc. I browse the forum and have invited people who I think look to have a reasonably decent personality about them, are people who I think will have fun in my rp, offer a lot to it, and are people who I think would make great friends with myself and the other players in the rp. It's always a risk, but a closed, invitational only rp is a lot less risky then a generally open rp. It's also a lot more limiting, and blocks you from meeting other possible new players, but with the stage my rp is at atm, and the fact that I have a solid group of players already, I don't really want to add an x factor I haven't properly researched that could end up ruining things.

Dervish said
Depends on the scale and what you're doing. I tend to like open RPs, but I've had some great experiences with invite only games. Normally, I just stick with the tried and true bar of entry to ensure the players are all at a similar skill level and motivation before starting.

This is the best answer because it does what all the others do in their ramblings in just one paragraph.

In all seriousness though? Whichever makes you more comfortable. I make public role plays but blatantly show personal favouratism towards people I know and can trust in terms of positions of power and limited slots. The "core" group, with anyone else tagging along and giving it a shot if they want to, and if they prove themselves, becoming part of the core for future role plays.