Add dataset card for crosshoming

DATASET_CARD.md

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+---
+language:
+- en
+license: mit
+task_categories:
+- tabular-classification
+tags:
+- economics
+- crosshoming
+- computational-economics
+- platform-economics
+- emerging-terminology
+pretty_name: Crosshoming Economics Dataset
+size_categories:
+- n<1K
+---
+
+# Crosshoming Economics Dataset
+
+## Dataset Description
+### Summary
+Synthetic 200-row dataset for `Crosshoming` measurement and computational experiments.
+
+### Supported Tasks
+- Economic analysis
+- Platform Economics research
+- Computational economics
+
+### Languages
+- English (metadata and documentation)
+- Python (code examples)
+
+## Dataset Structure
+### Data Fields
+- `id`: Unique observation id
+- `week`: Synthetic weekly platform activity
+- `multi_platform_participation`: Share of agents active on multiple platforms
+- `platform_switch_frequency`: Frequency of cross-platform activity switching
+- `portability_ease`: Ease of transferring identity/reputation across platforms
+- `exclusivity_constraint`: Strength of exclusivity clauses/incentives
+- `coordination_cost`: Operational coordination cost of multi-platform use
+- `revenue_diversification`: Diversification of revenue across platforms
+- `lock_in_intensity`: Platform lock-in pressure
+- `crosshoming_index`: Composite term index
+
+### Data Splits
+- Full dataset: 200 examples
+
+## Dataset Creation
+### Source Data
+Synthetic data generated for demonstrating Crosshoming applications.
+
+### Data Generation
+Channels are sampled from controlled distributions with correlated structure. The term index is computed from normalized channels and directional weights.
+
+## Considerations
+### Social Impact
+Research-only synthetic data for method development and reproducibility testing.
+
+## Additional Information
+### Licensing
+MIT License - free for academic and commercial use.
+
+### Citation
+@dataset{crosshoming2026,
+title={{Crosshoming Economics Dataset}},
+author={{Economic Research Collective}},
+year={{2026}}
+}