Dark patterns: what are most unethical UIs and growth hacks that you're aware of?

Back in 2010, the Hacker News community helped kick off the ‘dark patterns’ initiative [1]. You guys were awesome, darkpatterns.org [2] benefited hugely from your input.

If you’re not aware, the purpose of darkpatterns.org is to make people aware of the types of manipulative practice that are out there, and to name and shame the sites that use them. Scams don’t work when the victim knows what’s going on. Also, as a professional it’s just interesting to know what other people are up to, and where we should draw the line.

So, I’m intending on investing some more time on darkpatterns.org over the next few months and I could really use some help from HN.

My question to you is - what are most unethical UIs & growth hacking practices in use today? Please don’t be shy, name and shame.

[1] https://news.ycombinator.com/item?id=1511201 [2] http://darkpatterns.org/