I will say, the way the article is worded, you could take from it that Skype might be trying to parse your active conversation to offer up contextually relevant ads, which to some people would be incredibly invasive, not to mention prone to displaying insensitive ads...

Imagine a grieving mother talking about the recent loss of her son, and the ads being offered up are for childrens' clothes or child friendly activities.

Over all though, it's just one more spot they're putting ads on. By now, this is nothing new.