Removing personal info from web?

I'm wrapping up an Ethical Hacking course this semester and I think it's safe to say that most people would be really freaked out by some of the forensic tools that have been developed for not only collecting information but establishing the relationships between the pieces of data. There are tools that will allow you to put in one piece of information it will scour the public Internet for e-mail addresses, physical addresses, social media accounts, postings on non-social media sites, e-mails sent, documents created by the individual, phone numbers, pictures...you get the idea. The software presents it all in a graph-like format so you can click your way through and expand on whatever you want. Some more nefarious tools use common exploits to attempt to get not-so-public information. In theory, any information that you've provided to an entity that is connected to the Internet could be at risk. Utility companies, banks, retail stores, your employer, etc. It's very difficult to be truly off the grid, but some people are.