Googleโ€™s changes to its algorithms by year.

Each year for the last 5 years Google has done revisions to its algorithm to promote better user experience. I am sure you have heard people speak of these changes but what were they and what was the reason behind these changes?

2009:
Googleโ€™s โ€œVinceโ€ update saw big brands get a boost in SERPs
2010:
Google released โ€œCaffeineโ€ and revealed a new web indexing system
2011:
Google launched โ€œPandaโ€ and it started enforcing and regulating its guidelines when it came to โ€œthinโ€ content
2012:
Google launched โ€œVeniceโ€ and saw โ€œlocalโ€ search results ranking for more general and broad queries without a geo targeted modifier.
Google launched โ€œPenguinโ€ โ€ and it started enforcing and regulating its guidelines when it came to low quality links. (Links not relevant, bad neighborhoods, etc.)
2013:
Google launched โ€œhummingbirdโ€ which revealed a search engine that was more understanding of what users were searching for instead of just indexing results.