Each has it's place, and as long as you know what that is, I think you can use both. For example, due to life/work comittments, neither I or my language partners can have a 30 minute Skype conversation whenever we wish. We normally have to schedule it a day before so that the time is convenient for us both.

What happens if I have a question outside of that agreed time? I guess I could write it down and wait for the next session, but I use groups for asking questions at random times of the day and I normally get a quick reply as there is a large pool of native speakers. It's impossible to follow the complete thread of the group as different people are active at different times, and you also have the time zone issue.

Whatever phrases I learn from the groups, I'll then try to use in my one-on-one skype sessions.

Hi, I wanna learn to you.

My name's Beer. Nice to meet you.

:) 

@ Saqib Thank you for enlightening me. It seems my group is inactive plus I can see the benefits of groups.

I have a few native conversation partners and we ask questions via Skype messenger. I know I can get a response quite quickly too. Also you could pose questions here on Italki which also has an even larger pool of native speakers and teachers.

So Skype and whatsApp or any other app are just tools in aiding the language learning process. How good they are is determined by how active and how good the participants are.

Maybe it's just me. You see all these messages on joining a whatsapp group. You join and then you hear nothing. Perhaps there is something I should be doing. So I would like others to enlighten me.

So I have no experience of whatsApp groups so I have to agree with you.