That's not how Skype groups in particular, and collaborative efforts in general, work. You don't presume to know what is and is not a quality that you desire, and the idea of "leaching" is otherwise known and LEARNING, and if you start out right from the beginning that you don't want anyone trying to LEARN something then why bother having the skype group.
So then you say "Oh, I meant people that are only there to learn, and have nothing to give back." to which the response is, What makes you qualified to know in advance what people do and do not have to "give". So a person doesn't know something about something (such as SEO) and you assume that since they don't know SEO, they have nothing to "give" and that's just straight-up retarded.
I teach what I know about SEO and learn about the news broadcasting industry. I teach what I know about computer repair, and I learn about BitCoin. Your fundamental notion that you are somehow qualified to predict who is and is not going to be useful for a project that doesn't even exist, filled with personalities that you don't know who have skills and knowledge bases that you are completely unaware of and yet you just KNOW that you don't want any "Leechers".
For myself, *I* don't want self-appointed leaders with such obvious, deep and fundamental flaws in their ability to understand that just because things are unknown does not mean they are not HIGHLY desired. You have NO IDEA what critical piece of information makes the difference between success and failure, in advance of meeting that person, yet it is HIGHLY arrogant AND retarded to presume to not only know this, but then to advocate on behalf of excluding people based on what you think they do and do not know.
Meaning, you have no clue about what the purpose of an open and collaborative online effort is all about and from that position of ignorance you presume to have the power to exclude people, and THAT destructive quality right there is a good one to exclude from whatever effort takes place. There's nothing wrong with not knowing something, and wanting to learn, however there IS something wrong with using your ignorance as some kind of "qualification" to exclude others.