Being contacted by a stranger didn’t alarm me; that’s part of the beauty of sites like Twitter and Facebook, which can help shape new relationships around common interests and friends. But the unexpected addition of romance threw me for a loop. I wasn’t sure how to proceed. Should I meet the man for a drink? I polled my friends.

“NO!” came one shrieking response via text; another friend shrugged, wondering why I was troubled about being unmasked. After all, I live online with few qualms. Facebook and Twitter, plus Foursquare, Tumblr and Instagram, are just the tip of the iceberg. Still, I wasn’t expecting fragments of my online persona to collide in such a jarring way. I’d left out specifics about myself, first to observe that dating site undetected, then to reinvent myself as an eligible bachelorette.

In the end, I didn’t go on the date. I wanted to introduce myself to a handsome stranger at my own pace, rather than be exposed in one fell swoop. I couldn’t reconcile the tectonic imbalance in power and information that came with the note: He knew so much about me, and I knew nothing about him.

But the experience raised a question I haven’t been able to shake. As digital identities become increasingly persistent across the Web, is it still possible to reinvent oneself online?

“We are all going through the uncomfortable experience of discovering just how much information about ourselves that we put out there,” said Ethan Zuckerman, a researcher at the Berkman Center for Internet and Society at Harvard, who studies online expression and the digital world. “As we casually go about our business, we are leaking all kinds of data that someone can piece back together.”