World's Fair 2025
Teaching Gemini to Speak YouTube: Adapting LLMs for Video Recommendations to 2B+DAU - Devansh Tandon
Overview
This talk details the adaptation of large language models (LLMs), specifically Gemini, for YouTube's recommendation system, aiming to improve user engagement for over 2 billion daily active users. The core thesis is that LLMs can revolutionize recommendation systems, potentially surpassing search applications in consumer impact. The approach involves creating a domain-specific language for videos and training a bilingual model capable of understanding both natural language and this new video token language.
Who should watch
- AI Engineers working on recommendation systems
- Product Managers seeking to improve user engagement
- Builders exploring LLM applications beyond traditional search
- Those interested in adapting LLMs for large-scale consumer products
- Engineers facing challenges with massive content corpora and real-time updates
Key takeaways
- LLMs offer a significant opportunity for recommendation systems, potentially larger than search applications for consumer engagement.
- A key innovation is the development of Semantic ID, a method to tokenize videos by extracting features, creating multi-dimensional embeddings, and quantizing them into semantically meaningful tokens.
- The process involves continued pre-training of a base LLM (Gemini) on YouTube-specific data, linking text and Semantic IDs, and understanding user watch sequences to create a bilingual model.
- This adapted LLM, termed Large Recommender Model (LRM), can be used for generative retrieval, producing unique recommendations by understanding user context and past behavior.
- Serving costs for LLM-based recommenders are a major challenge at scale, requiring significant optimization (e.g., 95%+ cost savings) for production deployment.
- Offline inference using LLMs can create recommendation tables, offering a way to circumvent real-time serving cost issues for certain use cases.
- Adapting LLMs for recommendation systems is more challenging than traditional LLM training due to the vast, rapidly changing corpus of videos and the need for near real-time updates.
- Future directions include interactive recommendation systems where users can steer suggestions via natural language and the potential convergence of recommendation and generative content.
Notable quotes
*Recommendations is going to be a much bigger consumer application than search.*
*We're making the atomic units for a new language of YouTube videos.*
*LLMs are just augmenting recommendations. They bring these magical recommendation experiences.*
Unofficial community note. Prefer the recording for nuance.