1) Interacting in online forums, pre-search engine, where such discussions where considered more-or-less ephemeral, and only available to a closed group of "Internet users" wasn't super-public. All of that is now archived and indexed. If you search for me, you'll find it.

2) Giving my data to super-credible companies, pre-spam. Wouldn't you know it? A few went out of business, and my data was neatly packaged up and resold to the highest bidder. One was an enterprise database company.

3) Personal web page ended up on archive.org, before anyone really knew others were grabbing/indexing/archiving things. It had more of the feel of your front yard. Yes, someone could take a photo, but it wasn't common.

4) The whole Yahoo thing. My emails become property of some data broker who now mines them for marketing and sales.

I obviously won't talk about more personal ones. And no one will talk about litigations. But those sorts of things happen too.

The things I worry about now are the really sophisticated fingerprinting mechanisms, where your typing patterns, your vocabulary, your linguistic quirks, etc. become biometric identifiers. I'm not sure how all that data will be archived, integrated, and combined 25 years from now.

History suggests Google won't be Google forever, though.

Oh, and let's not forget what happened with data, Jewish people, WWII, and Germany. That's beyond my timescale, but these things happen.