I am delighted to share that I'll be joining the University of Washington Information School as an Assistant Professor!

Wonderful talk by @sjgreenwood.bsky.social about @paper-feed.bsky.social! Custom feeds on Bluesky are unique resources for researchers interested in recommendation algorithms #IC2S2 Featuring many Bluesky friends like @graze.social @devingaffney.com @kissane.myatproto.social @aendra.com

One intuition behind many AI policy proposals is that downstream AI applications -- the companies deploying AI in healthcare, finance, education, customer service, etc. -- should bear responsibility for ensuring safety. Our paper asks: What incentives does that create for the firms building AI?

🧵Can we reconcile excitement for SAEs with negative results? Our #ICML2026 position paper argues that even if SAEs underperform baselines when acting on knowns (e.g. probing, steering), they're a powerful tool for ~discovering unknowns~ Poster: Tue 2pm, HALL A #1715

Are you at ICML next week? Feel like your decision-making for which sessions to attend might not be risk minimizing? Don't incur (swap) regret and come to my, @aaroth.bsky.social, and @ncollina.bsky.social's tutorial Monday on multicalibration, decision-making, and collaborative learning!

Presenting this at #COLT2026! Let me know if you want to chat about (1) the linear representation hypothesis, (2) theoretical foundations for interpretability / science of AI. - Talk: Thursday 2:33 pm - Deep Learning Theory / Optimization - Poster: Thursday Lunch)

Kenny Peng@kennypeng.bsky.social · 6mo ago

New paper! The Linear Representation Hypothesis is a powerful intuition for how language models work, but lacks formalization. We give a mathematical framework in which we can ask and answer a basic question: how many features can be stored under the hypothesis? 🧵 arxiv.org/abs/2602.11246

In college, I wrote this essay about Clark Kimberling, who maintains the Encyclopedia of Triangle Centers. The essay covers triangle geometry's rise (which includes Napoleon), its fall (from "brute force" methods), and its continued following ("the melody lingers on")

Coincidence of Lines

The mathematician Clark Kimberling estimates that he spends between two and five hours each day, seven days a week, maintaining his online encyclopedia of triangle centers.

leaflet.pub

We are very excited to announce our first workshop on From Theory to Practice: behind the scenes on research deployments at EC’26 (July 6 in Rome)! Call for posters and submissions now open! Organized by myself, @ericachiang.bsky.social , Bailey Flanigan, @brwilder.bsky.social

Two Bluesky client apps have integrated the "also liked" functionality: - @boostblue.bsky.social - iOS and Android - @skywalker.thereforeiam.eu - Android The app integration makes it a much smoother experience than the stand-alone website foryou.club/also-liked Here is how it looks in Boost Blue:

We made traversle.io, a new daily word game! The goal is to traverse from a start word to a target word through a network of related words. (Our motivating question: is it possible to construct a network that allows human navigation?)

Very cool — a way to jump from one post onto a trail of related posts. Lots of possibility and opportunity to push beyond the feed interface!

spacecowboy@spacecowboy17.bsky.social · 4mo ago

Introducing a new way to explore Bluesky: foryou.club/also-liked Enter a post URL to see what other posts people who liked it also like. For example, enter the url of this art post: bsky.app/profile/alar... and you will get a bunch more art posts: foryou.club/also-liked?p...

bluesky is dying? Come to the Wait and See feed

so cool! over 20k trails to explore…and that's just based on a single week of bluesky posts! fun to search trails & browse related ones…seems like a great way to find new folks to follow & prob closest thing I've seen to "collections" as @danabra.mov has been advocating for

skytrails · 20,000 trails through Bluesky

Regaining freedom of movement on social media. Browse Bluesky via interconnected trails.

skytrails.org

Kenny Peng@kennypeng.bsky.social · 4mo ago

🧵 On social media, we feel trapped in “filter bubbles” and “echo chambers.” Often, we see this as a problem with the algorithm. Our new essay argues the problem is the feed interface itself: it constrains our movement—all we can do is scroll. We lay out an alternative vision:

Loved reading this. The premise that social media should let us actively traverse it through connections, not just scroll a feed feels exactly right. One thought it raised for me: Trails (& rabbit holes) are often spaces we wander through alone. What would a more social analogy get us?

Kenny Peng@kennypeng.bsky.social · 4mo ago

🧵 On social media, we feel trapped in “filter bubbles” and “echo chambers.” Often, we see this as a problem with the algorithm. Our new essay argues the problem is the feed interface itself: it constrains our movement—all we can do is scroll. We lay out an alternative vision:

I have really enjoyed talking with Kenny about his work on alternative rec system mechanisms. This work offers a vision of user-powered concept exploration: imagine the social media feed equivalent of the joy of exploring wikipedia by navigating trails of hyperlinks from one article to the next.

Kenny Peng@kennypeng.bsky.social · 4mo ago

🧵 On social media, we feel trapped in “filter bubbles” and “echo chambers.” Often, we see this as a problem with the algorithm. Our new essay argues the problem is the feed interface itself: it constrains our movement—all we can do is scroll. We lay out an alternative vision:

🧵 On social media, we feel trapped in “filter bubbles” and “echo chambers.” Often, we see this as a problem with the algorithm. Our new essay argues the problem is the feed interface itself: it constrains our movement—all we can do is scroll. We lay out an alternative vision:

From Feeds to Trails

To design the future of social media, rethink the interface before the algorithm.

leaflet.pub

Excited to share our new research demo, where you can freely traverse the world of Bluesky through 20,000 interconnected trails, spanning “analysis of fictional tropes” to “rotisserie chicken” to “zoning and land use policy.” Try it out, and let us know what you think!

skytrails · 20,000 trails through Bluesky

Can we regain freedom of movement on social media? Browse Bluesky via interconnected trails.

skytrails.org

New in Nature Health: how might we move towards a world in which race is not used in clinical algorithms? We need (1) careful comparison of race-aware and race-neutral algorithms and (2) systemic efforts to address underlying disparities.

Had a great time presenting our work on building MIGRATE–a new dataset of US migration–at the @geographers.bsky.social AAG Annual Meeting today. Happy to also share that we received an AAG student paper award for this work!!! Come chat if you are at #AAG26 this week. migrate.tech.cornell.edu

Our paper, "What's in My Human Feedback", received an oral presentation at ICLR! Our method automatically+interpretably identifies preferences in human feedback data; we use this to improve personalization + safety. Reach out if you have data/use cases to apply this to! arxiv.org/pdf/2510.26202

New paper! The Linear Representation Hypothesis is a powerful intuition for how language models work, but lacks formalization. We give a mathematical framework in which we can ask and answer a basic question: how many features can be stored under the hypothesis? 🧵 arxiv.org/abs/2602.11246

Our paper “Inferring fine-grained migration patterns across the United States” is now out in @natcomms.nature.com! We released a new, highly granular migration dataset. 1/9

🎙️ I had a great time joining the Data Skeptic podcast to talk about my work on recommender systems If you're interested in embeddings, aligning group preferences, or music recommendations, check out the episode below 👇 open.spotify.com/episode/6IsP...

Fairness in PCA-Based Recommenders

open.spotify.com

Check out our new paper at #AAAI 2026! I’ll be presenting in Singapore at Saturday’s poster session (12–2pm). This is joint work with @shuvoms.bsky.social, @bergerlab.bsky.social, @emmapierson.bsky.social, and @nkgarg.bsky.social. 1/9

Excited to present a new preprint with @nkgarg.bsky.social: presenting usage statistics and observational findings from Paper Skygest in the first six months of deployment! 🎉📜 arxiv.org/abs/2601.04253

so so so excited to present our research + connect with the #ATScience community 🧪🎉

ATProto Science@atproto.science · 7mo ago

Excited to announce that @sjgreenwood.bsky.social will be at #ATScience presenting their work on the beloved @paper-feed.bsky.social , experiments on self-hosted feeds (in collaboration with @graze.social @aendra.com) and observational analyses of social media on #atproto! Looking forward to it! 🎉

Year 3 of spending many days making gingerbread — this year, featuring the gantries of Long Island City

Excited to share a new working paper! What happened when Change.org integrated an AI writing tool into their platform? We provide causal evidence that petition text changed significantly while outcomes did not improve. 1/ arxiv.org/abs/2511.13949

Introducing AI to an Online Petition Platform Changed Outputs but not Outcomes

The rapid integration of AI writing tools into online platforms raises critical questions about their impact on content production and outcomes. We leverage a unique natural experiment on Change$.$org...

arxiv.org

I had a lot of fun making this map of Manhattan’s grid (only the numbered streets and avenues). Learned that 4th avenue doesn’t exist, but then learned that it actually does exist but only for a few blocks.

Urban Data@urban-data.bsky.social · 9mo ago

For #30DayMapChallenge day 11, a minimal map from @kennypeng.bsky.social. Kenny extracts minimal elements from a not-as-minimal-as-it-seems object: the Manhattan street grid. "I show how Manhattan’s numbered grid of streets and avenues is more complicated than you might realize," he says.