During the last months of 2012, and as a part of AyerViernes, we worked on one of those projects that is as challenging as delightful to take part in, developing a unified search system for a network of over 200 WordPress sites (both single-install and multisite).

We developed a real-time sync plugin integrating the WordPress sites with an Elasticsearch instance with different content types (mappings) that give us plenty of room to index and search in hundreds of thousands documents generated by the university staff.

You can read the complete post (in spanish) on Medium: Desarrollo de sistema de búsqueda transversal: +200 sitios a un clic de distancia