That solution is “light accounts” and it is our hope that the community, and the Witnesses they elect, will consider this feature for inclusion in the SMT hardfork.

Could you be specific please.

Does this mean HF21?

If you are serious and have or will have the code ready for testing and approveal by witnesses in the next couple of weeks-ish (maybe less) please let us know or we will likely have to just consider this something for 2020 or 2021... because the next hardfork after this one is likely not gonna arrive until 2020 and that's not a good enough solution for @steempeak in my opinion.
We were about to start down another road but we like this decentralized option better.

WHAT EXACTLY WILL A LIGHT ACCOUNT DO?

You were pretty vague on what a light account can do.
Even a short list would be nice.

• Comment?
• Send receive money?
• Create JSONS (thus handle many types of apps)
• I assume probably not stake steem for Steem Power and vote.
• I also assume probably not create posts but seems like Comments would be important... but technically the two things are pretty similar.