Spreadsheets were arguably the first Killer App for personal computers, a tabular ledger but also a kind of visual dataflow language. However, the standard spreadsheet has some pretty severe problems... sometimes, it really is time to reinvent the wheel!
Why is it that every case is an exception to a rule?
What if you could have a rich web frontend without developing one?
Editing an AST in the browser
What if there were no functions?
Are programs really text files?
IoT Networks without IP? Madness. But ... maybe ...
I was talking to $PERSON from $BIG_COMPANY the other day, and they happened to mention that around 80% of their CPU time was spent on serializing and deserializing data ...
From the "Ideas I'm Never Going To Implement Myself" bucket: NoMail is an email service which doesn't store anything. Anything at all. Email received by NoMail is ephemeral and exists only in your client.
Image a WWW using Cryptographic Hash URIs instead of URLs.