Ask HN: What is the best social sharing service API out there?

There are a tons of social sharing mashup services out there that allow for easy social integrating of your website.

I have located some of those services, to name a few as an example of what i am talking about: http://www.addthis.com/ http://sharethis.com/ http://www.shareaholic.com/ and http://easy-share.com/

For a web developer building his startup, requiring advanced customization and configuration options, which would be the best solution for social sharing mashup services?

What is your experience?

I also added this question on quora: http://qr.ae/7KnB4