We are partners for Oracle and SAP and there are a lot of customers who are using Oracle Taleo as a cloud solution from our side.
I believe that Taleo has been in the market for the past 20 years or more, and was a separate company before being acquired by Oracle. In general, Taleo was first and foremost used for recruiting, onboarding, and then performance management and goal management. Later, they acquired Taleo Learn and they now also have a learning management application under Taleo's umbrella. However, lately they are moving more to ORC (Oracle Recruiting Cloud).
Taleo's user base differs from client to client, but most organizations have around 3,000 users. Oracle Taleo also has a Business Edition module, so customers have an option here. With a large user base, organizations can go with the Enterprise Edition, or if there aren't that many users, they can go with Taleo Business Edition.
The most usable and well-known feature is Oracle's recruiting module for Taleo. Performance and goal management are good to have, based on certain client requirements where the user base isn't too large, but the most workable domain of Taleo is the recruiting module.