content: And they can still mine it if you interact with anyone using those services. Send an email to someone at a Gmail address? Your info is tagged, categorized, and neatly tucked away for future use. Visit a page with a "Share on (Facebook/Twitter/Pinterest/NSA)? At least with the Facebook ones I recall reading somewhere that every time Facebook served up that script it would track you. So even if you didn't ever have a Facebook account or go to their website directly, they still had info on you such as your browser info and what sites you visited. Using your browser info they would try to create a unique ID for you then track that across all sites that use that script.