MS and FB are practically the same ethics-wise to me. I'd be interested to hear more of your thoughts on this.
Google and Facebook would have been worse for Skype, they both suck at privacy.
Historically we can see that companies (especially corporations) are as ethical as the laws force them to be, especially when it comes to decisions affecting the bottom line.
People themselves have ethics because that's the only way of living in a society -- discerning between good and evil, making decisions that aren't hurtful to others -- these are standards we live by because they work best in improving our own quality of life.
Historically, we can see that people (especially leaders) are as ethical as the laws of their society force them to be, especially when it comes to decisions affecting their well-being (which quite often is their bottom line).
In society when people misbehave, they get marginalized, discriminated against, even abused. E.g. for rapists punishment doesn't stop immediately after jail-time was served, for some unlucky ones the real punishment only begins after getting out of jail.
Things like peer-pressure, the board of directors,
profits, strategy, market pressure and so on can
make good people do bad things.
You can look at a company and try to analyze its decisions from an ethical point of view, but that is just using a convenient and familiar simplification to understand a complex entity. One can say that a company is "good" or "bad" or "immoral", one could even say that it has goals and ambitions as someone mentioned earlier, but how useful is this really in trying to understand that company and in predictiing its actions?
* Most of the services they provide are free (with a hidden privacy tax).
* They make most of their money based on analyzing their user's data.
* Both have a hostile attitude towards privacy, claiming that it's dead, trying to make it look old fashioned and irrelevant.