GoBase

GoBase is a website by Jan van der Steen that contains a large collection of professional games, as well as a number of articles, including study material.

gobase.org

Between roughly 2009 and 2014 the site was no longer actively maintained. However it was updated quite substantially in January 2015.

It has a database search engine for searching through the collection and includes an online replayer that can display the games found in the database.

A large part of GoBase, including the replayer, requires an username and password to access. Registration for the username and password was free. As of 5 August 2007, there is a 20€ fee in order to register an account. Registration must be done from a non-anonymous and non-free email account, failing which extra credentials must be supplied.

Gobase has an RSS feed available. If you use LiveJournal, you can add the gobase feed to your friends list.

See also 321 Go which is described by GoBase as its little brother.