Has anyone built anything useful using AI?

Yep.

Curious to know this too.

I miss the pre LLM days on HN when hype was spread around various topics instead of it just being about AI.

No. They are hype.

I have used coding agents with great success. So in some way I'm building useful things using AI, and the people who created those agents absolutely created something extremely useful.

I think people in the content business have probably seen the most significant boost from AI, so far.

I have. The advent of "reasoning" llms means you can trust them with judgments.

Chatgpt basically invented it in september of 2024. We are only coming up on the concept's 1st birthday. Open source options have only been out for 6 months.

I highly recommend using these for your own purposes.

yes!

Use it everyday https://github.com/jharohit/team-timezone-wall

Also built a AI NDA tracker for all our NDAs in the company which is awesome! We will open source soon.

Lots of "information extraction" tools - basically taking in a bunch of documents and other natural language material and pulling out a few key pieces of structured data. This isn't 100% reliable but is useful as a first pass (where a human can investigate further) or a backstop (against a human missing something important and obvious but buried in a long file or huge volume of files).

I also put together a half-baked web extension to try to steer the Youtube algorithm. It basically scrolls through shorts and tries to watch+like high quality content and skip+dislike junk (and worse) to scrub it out of the feed as much as possible. It's only looking at the transcript and a couple of thumbnails, so it's not super accurate, but in the short term it's been working pretty well. I figure that Google can probably tell that it's not a human though, and might disregard its inputs (or ban me) in the long term. Time will tell.