I thought this was harmless, when I found out that there are numerous 3rd party websites who scrape data in social networks, newsgroups, even app reviews. This shifts the control outside your hands. Remember when there's a story about how you can't remove data from a service provider ? It doesn't matter if Google/Twitter/Facebook/others support removing my data and public posts, it means that I have to hunt down other parties to do the same, as they don't update their data and no one knows that app review I wrote is 3 years old and the account doesn't even exist anymore.

That's also why I'm done with the Internet and real name policies.