She had me at hello ... or just about. Our conversation had barely started when privacy activist Betty Ostergren interrupted me to say that she had found my full name, address, Social Security number and a digital image of my signature on the Web.

I had set out to discover just how much information I could find about myself online, and Ostergren, who runs the Virginia Watchdog Web site, was my very first call. If this was what could be uncovered in just a few minutes, what else would I find? Quite a bit, as it turns out.

What information is available about you in cyberspace? Where does it come from? What risks does it present and what, if anything, can you do to protect yourself? To answer those questions I decided to use my own identity, Robert L. Mitchell, a national correspondent at Computerworld , as my research subject.

Starting with the information Ostergren had turned up about me, I spent a few weeks combing through more than two dozen public and private resources on the Web and visiting many other Web sites to build a dossier on myself. I conducted both free and paid searches. I contacted a private investigator for tips on my investigation. And I spoke with data aggregators and privacy experts.

I quickly discovered that while the quantity of publicly available information about individuals to be found online is vast, it is riddled with inaccuracies. For example, I changed my primary residence more than a year ago, but many databases online still have my old address. In other cases, the information is just plain wrong.

Having a common name like Robert Mitchell -- or a famous one like Bill Gates -- makes the job a lot harder. While nuggets of information about you can be pulled up quickly, filtering out all of the data that is not actually about you and sorting out what is accurate is time-consuming. It requires a lot of digging.

But I was starting with a key piece of data -- my Social Security number -- and that makes finding relevant data a bit easier. As I gathered more data, I also reran many searches to get different -- and more targeted -- results. Here's what I found and where I found it.

Source: Government records

Information discovered: Full legal name, address, Social Security number, spouse's name and Social Security number, price paid for home, mortgage documents, signature

Much of the publicly available information on individuals online is sourced from online county, state and federal government records databases, and this is where Ostergren found my Social Security number. She hadn't purchased it from a hacker chat room or from shady characters in Russia. She got it by browsing an image of a mortgage document stored in a county database located in a building half a mile from my house.