Not to mention if you care about the privacy of your users every share button is a little tracking device that probes into your users habits and pages visited. (Ghostery can help you see the extent of the tracking that is taking place)
I get really mad at share buttons because there's no way to know beforehand if you are going to get to a page filled with those.
From observation I came to a simple law about these share buttons: the amount of content is inversely proportional to the number of share buttons on the page.
If you haven't already, check out "request policy".
It's a plugin I'm using in FF alongside noscript. It makes browsing kind of noisy, but educational. As with your observation about 'like' buttons, I notice the more craptastic sites often try to pull content from 10+ other domains. ( Request policy stops these cross domain requests until approved )
Regarding Ghostery, there is really no way of observing what is being logged and what isn't on the server. Only some sort of legal inquiry can reveal that (eg what happened with Facebook in Ireland)
You could also use noscript or disable third party cookies in browser settings if you really don't want social media buttons.
You can still, however, make your own buttons using the API calls from the related social sites. You do not have to use the standard buttons provided. This way you can avoid all the privacy issues.
I get really mad at share buttons because there's no way to know beforehand if you are going to get to a page filled with those.
From observation I came to a simple law about these share buttons: the amount of content is inversely proportional to the number of share buttons on the page.