It shares some information that you optionally choose to share (genealogical data like where your ancestors are from, family names, etc., and which segments of

It shares some information that you optionally choose to share (genealogical data like where your ancestors are from, family names, etc., and which segments of DNA match). One thing reading Hacker News has made clear is that people have wildly differing opinions of what "sensitive" and "risky" mean.