Google publishes a lot of papers. PageRank, one of the the original key algorithms for Google search, was released to the public. Unfortunately, this empowered spammers to game the search engine and create link farms & other “gems.” That’s a big reason why they don’t share in that space any longer. Too many people looking to exploit search results by any means necessary.

On other topics, Google has been the sole inspiration for some substantial projects. AI aside, their paper on BigTable (their own product) caused a ton of interest and sparked independent projects like Hadoop, HBase, & Cassandra). The modern way we work with big data is thanks to Google.

In any case, Google has no obligation to give away algorithms or the designs for entire products, yet they often do.