I think italki is very suitable to meet language partners but since it unfortunately doesn't offer voice chat or even a decent chat, and message exchange is quite basic, it is necessary to use other communication means if you are interested in a serious language exchange. Of course, you are free to use the site in any way that suits you, so if you are only interested in exchanging messages on italki your language partners will have to take it or leave it. However, in my view, the voice chat can greatly improve the language learning experience. If you decide to use it, I would suggest to choose a small number of people that you are really going to talk to, and share your contact only with them. You should first exchange some messages and review their profile to see if they are serious and suitable as your language partners. Many people here want to add you, I don't really know why and what for, but never really want to talk to you, so no need to accept everyone who asks. Of course, there is always an option of opening a skype account or even a facebook account that do not contain any information you don't like to share with too many people, and only use it for language learning purposes.

I completely understand about not wanting to give relative strangers your Facebook information.  I wouldn't do that either. People are probably asking for your skype information because that is how they'd like to practice a language with you. Do you want to find a language partner? Do you use a different platform other than Skype?

i created a completely new Skype id when I started on italki  

In terms of privacy this issue, I consider many language learners would not give their partners facebook pages and for sure, that is a good idea to adopt skype as a good tool to practice a language.  I cannot agree with more.