Short:
Build a community website, where people can mark reminders depending on maturity of technology.Volunteers can then organize those reminders, keep track and send reminders back (Either manually or automatically).
Eg1: Remind me when the norm of RAM in PCs is 8 GB.
Eg2: Remind me when
we have light source that gives 800lumens in under 3 watts and costs $5]
Long (or why) :
There are a lot of ideas and dreams that we have when technology is a bit immature. Like you might get an idea for a software, that will be feasible only if all desktops at least clock 6 Ghz or 20 GB RAM becomes the norm or When the internet speeds on your cellphones are 80 mbps. Or you might get an idea for a car fixture, which will be usefull only when at least 60% of the cars in the world are electric. Or you might get an idea which might be nice to implement when LCDs are cheap enough to be everybody's curtains.
All these ideas come up during the "semi-fantasy" stage, when you know the technology is just out of reach. The anticipation phase. But what eventually happens is, when the technology finally arrives they will be taken for granted and the fascination would be lost, most ideas and dreams would sadly have been forgotten, which would have otherwise made the world a more interesting and better place.
I had a tonne of ideas on what can be done with a laptop, when laptops were a luxury items, enjoyed by the elite rich community. Now its so cheap, I have two laptops, both twice as powerfull than what I had dreamt of, and I can't remember a single idea of what I wanted to do with them. I can't remember a tonne of ideas I had about portable touch screen devices. I own two phones, both with powerfull processors, running Linux and have touch screens.