Here are some of the ideas that seemed outlandish in their day, but became common sense by 2018.
Blippy's crazy card-sharing social network
It launched in December 2009, allowing users to register a credit card with the site to track — and publish — users' purchases at merchant sites including iTunes, Amazon.com and Netflix.
The idea horrified many who feared that this information could be used for identity theft or other nefarious purposes. And these fears were validated when, in early 2010, Blippy confessed to a mistake during beta testing that exposed raw transaction data to Google's search engine, rendering it visible to the wider internet. This data included sensitive information such as airline-confirmation numbers, which could be used to impersonate a flight passenger.
Blippy patched the issue and explained what happened, but the issue compounded itself when alarmed customers tried to remove their card accounts from Blippy — only to find their accounts inaccessible due to an overload of site traffic.
The idea may have fared better in today's age of social oversharing, where platforms like Venmo, Snapchat and WeChat built a loyal user base despite the risks of making too much personal information — and payments information — accessible in one place.