Common Crawl provides an archive snapshot dataset of the web which can be utilized for massive array of applications. It is also based on the Heritrix archival crawler making it quite reusable and extensible for open-ended solutions whether that be building a search engine against years of web page data, extracting specific data from web page documents, or even to train machine learning algorithms. Common Crawl is also available via the AWS public data repository and accessible via the AWS S3 blob store. There are plenty of MapReduce examples available in both Python and Java to make it approachable for developers. Having years of data at a developer's disposal saves one from manually setting up such crawler processes.
