The document discusses mashups, which are combinations of data from two or more independent sources presented in an unanticipated way. Mashups often use "glue logic" to connect different types of data. Examples of mashups include combining search results with RSS feeds, using presentation tools to display RSS feeds, and filtering blog categories and tags to emergently link blog posts. The document promotes experimenting with different tools and APIs to "mash it up" and create string'n'glue learning environments.