You asked about Hydrogen Energy
16 people built something like it. 16 are gone.
That is 100% of the ones whose fate we could settle, against 23% across the whole register.
| Launched | What it was | Today |
|---|---|---|
| 2022-01-01 | First commodity marketplace for hydrogen. · phoenixhydrogen.com | gone |
| 2021-01-01 | Mobile Energy Storage Technology · moxionpower.com | gone |
| 2017-06-01 | Sunfolding builds next generation infrastructure for solar farms. By… · sunfolding.com | gone |
| 2017-06-01 | YCNextDrop NextDrop is the water marketplace for urban India. We connect water… · thenextdrop.com | gone |
| 2019-01-01 | AI driven professional engineering firm · traverse.ai | gone |
| 2022-06-01 | Claim solar incentives with AI · jasmine.energy | gone |
| 2021-01-18 | teznic.com | gone |
| 2022-01-01 | YCPelm Plaid for utilities · pelm.com | gone |
| 2019-01-01 | We deliver affordable renewable energy direct to customers and are… · getgex.com | gone |
| 2020-06-01 | YCOneKey Find the most profitable sites to build EV charging station · getonekey.io | gone |
| 2023-06-01 | Incentives and financing for energy efficiency upgrades · line.build | gone |
| 2023-06-01 | AI Energy Management · trycardinal.ai | gone |
| 2016-06-01 | Nanoparticle tracers for reservoir characterization during hydraulic… · gtracktechnologies.com | gone |
| 2015-06-01 | Building the lowest-power silicon for embedded deep learning and… · remicro.com | gone |
| 2017-06-01 | YCWATERFX The world's first 100% sustainable water provider (aka alternative… · wacomet.com | gone |
| 2009-01-01 | Sensors and software for energy tracking. Like 'fitbit' for your… · wattvision.com | gone |
How this compares
Y Combinator reports its own outcomes, including acquisitions. The other two are judged by asking the domain, so they are not measured the same way and are never averaged together.
The register re-probes every domain it holds. Some that answered last month stop answering. We send that list — what went quiet, and what it was — once a month. Nothing else.
How this was made. Show HN entries are every post from 2021 to 2023 with at least five points that linked to its own domain; code hosts and free hosting are excluded, because a repository outlives the effort behind it. Product Hunt entries needed 100 votes — a far higher bar, so they are the promoted top slice rather than a like-for-like sample. Both are judged by asking the domain whether it still answers: gone means it no longer resolves, refuses the connection, serves a parking page, or says plainly that it shut down. An HTTP error is not counted as gone — a server answering 404 is one somebody still pays for, and an audit of 25 gone-calls found two such sites alive with only a moved homepage. Y Combinator entries use the status YC publishes itself, which is why only those can say acquired. Squatted domains — a lapsed name now serving somebody else's site — are not detected, so these figures run slightly low.