Rethinking User Encoders: Routing Diffusion States for Scenario-Adaptive User Representation
Original reporting by arXiv (cs.AI)

Existing large language model (LLM)-based user encoders convert diverse user behaviors into static digital profiles, yet frequently struggle to capture the full complexity and dynamic requirements of real-world applications. These systems typically compress heterogeneous behavioral logs through unidirectional autoregressive prediction, which limits information flow, hinders cross-modal interactions, and struggles to jointly preserve multi-source signals. The resulting static representations therefore fail to accommodate the distinct evidence requirements of diverse downstream scenarios, from personalized recommendations to fraud detection.
Dynamic Representation
Addressing these limitations, a new framework named FINDERS (FactorIzatioN of Diffusion statEs for Routing across Scenarios) unlocks the iterative denoising process of diffusion language models (dLLMs) as a multi-granularity reconstruction space. FINDERS reimagines user encoding, moving dLLMs beyond language generation to create highly dynamic and adaptable user representations. Comprising denoise, factorize, route, and compress operations, FINDERS uses learnable meta-slots to organize complementary denoising states into transferable cross-modal semantics and modality-specific behavioral factors. Supervised by a novel large-scale BehaviorQA corpus, a lightweight router dynamically emphasizes relevant behavioral dimensions based on scenario queries. This innovative approach has consistently outperformed state-of-the-art methods across ten industrial scenarios in extensive experiments and online A/B tests, demonstrating dLLMs’ immense potential as powerful user representation learners.
The FINDERS framework marks a pivotal advancement in user representation learning, successfully addressing the inherent limitations of static, autoregressive models. By creatively harnessing the iterative denoising capabilities of diffusion language models and integrating a sophisticated routing mechanism, FINDERS generates dynamic, scenario-adaptive user profiles. Its demonstrated superior performance across ten industrial scenarios, validated through both extensive experiments and online A/B tests, confirms its efficacy in unifying diverse behavioral signals while remaining responsive to specific contextual demands. This breakthrough not only pushes the boundaries of dLLMs beyond their conventional generative applications but establishes them as potent tools for complex, multi-source data interpretation.
Broader implications
This innovation carries profound implications for the future of personalized AI. The capacity for models to dynamically emphasize relevant behavioral factors based on specific scenario queries promises a new era of highly context-aware systems. From significantly more accurate recommendation engines and predictive assistants that anticipate user needs, to adaptive interfaces across e-commerce, healthcare, and education, the ability to build and route nuanced user representations will enable AI to interact with individuals in a more relevant and responsive manner. Furthermore, by proving the versatility of dLLMs in non-generative tasks, FINDERS inspires new research directions, potentially fostering a paradigm shift in how we approach user modeling, paving the way for AI systems that truly understand and adapt to the multifaceted complexities of human behavior in real-time.
Frequently asked questions
- What are the drawbacks of existing large language model user encoders?
- Existing LLM-based user encoders typically process behavioral logs unidirectionally, creating static user representations. This limits their ability to capture bidirectional information flow and interact across different data modalities effectively. Consequently, these static representations often fail to adapt to the specific information requirements of various downstream AI applications and scenarios, leading to suboptimal performance in dynamic environments.
- How does the FINDERS framework enhance user representation in AI systems?
- The FINDERS framework improves user representation by leveraging diffusion language models (dLLMs) for iterative denoising. It processes user behavioral data through four operations: denoise, factorize, route, and compress. This approach captures complementary cross-modal semantics and modality-specific factors, which a lightweight router then dynamically emphasizes based on specific scenario queries. This allows for more adaptable and context-aware user profiles, outperforming static methods in diverse industrial applications.
- What role do diffusion language models play in learning user behavior?
- Diffusion language models (dLLMs) are utilized to learn complex user behavior by enabling an iterative denoising process, which acts as a multi-granularity reconstruction space for behavioral logs. Unlike traditional autoregressive models, dLLMs allow for bidirectional information flow, facilitating better cross-modal interactions and the joint preservation of signals from various sources. This capability helps in constructing dynamic, scenario-adaptive user representations that overcome the limitations of static models.