Increase their face - on social skills by encouraging and facilitating situations where they interact with other people. It's worth a think about why kids use skype etc so much here! Not so long ago or 'at home' they would have been playing out in the street or calling in on each other without the restraints of organized 'play dates'. Skyping etc is sometimes the only form of being with friends after school that kids have ! Or .... You could just pull the plug!
Why do they use skype so much...............well in my day (and it was quite a while ago and not so hi-tech!) it was the phone and our parents were always moaning about the bill (things don't really change that much, the method might but the end result doesn't ie the complaining parent!). Now skype is free so what do they moan about.............the time you spend on there.
We ditched playing out in the street aged about 11 - OP doesn't say how old the kids are but I'm guessing not primary (or at least late primary). Playing out in the street is all well and good but kids do grow out of it eventually (whether it's 1911 or 2011)
When I did play in the street I played with kids who lived in the same or next street - over here, not many "same street kids" go to my kids school - skype/facebook etc is just a way of keeping in touch - that or a $20 cab ride/2 hour bus ride.......I have to say, I'd rather they used skype than that every night.