Recommendation Engine SaaS 2009-2026 (差別化: ML Recommend API Service軸)。Amazon Recommendations 1998 Item-to-Item Collaborative Filtering (Linden+Smith+York 2003・「Customers who bought this also bought」発明・Industry先駆け)・Netflix Prize 2006-2009 ($1M賞金・SVD Matrix Factorization+Collaborative Filtering革命)・Algolia France 2012 (Search+Recommend Personalization・Search Engine起源→2019 Recommend追加・$200M ARR)・Recombee Czech 2014 (Recommendation as a Service・Pure ML Recommendation・E-commerce Product+Article+Video・Hybrid CF+CB+Deep Learning)・Constructor.io USA 2015 (Search+Browse+Recommendations・Sephora+Bonobos+Backcountry)・Klevu Finland 2013 (Search+Discovery・Shopify+Magento)・Bloomreach USA 2009 (Discovery+Engagement・Headless Commerce)・Coveo Canada 2005 (Enterprise Search+Recommendations)・Monetate USA 2008→Kibo 2019 (Personalization Testing+Recommendations)・Dynamic Yield McDonald's買収 2019→Mastercard 2022 (Personalization)・Personali Israel→Bloomreach・Salesforce Einstein Recommendations・Adobe Sensei Target+Real-Time CDP・Google Cloud Recommendations AI+Vertex AI Recommendations・AWS Personalize・Microsoft Azure Personalizer・OSS: Surprise Python+LightFM+TensorRec+Implicit Library+RecBole+Microsoft DKN+Spark MLlib+Recommender Library・MediaPipe RecommenderXGBoost+RankNet+LambdaMART+DeepFM+Wide & Deep+Two Tower Neural・Algorithm: Collaborative Filtering CF (Item-Item+User-User+Matrix Factorization SVD)+Content-Based CB+Hybrid+Knowledge-based+Context-aware+Deep Learning DLRM Facebook 2019+Transformer-based BERT4Rec+SASRec Sequential・Cold Start問題・Diversity vs Novelty vs Serendipity Trade-off・¥¥¥¥¥-¥¥¥¥¥¥¥¥/Industry Algolia Premium ¥¥¥¥¥¥/月、2026年Algolia+Recombee+Constructor.io+Bloomreach+Coveo+Algolia Recommend主流・LLM Recommendation+Vector Embedding+RAG拡大。