Apparently Oracle has decided to release a version of their database for free to go against the growing competition from free and open-source databases such as Postgres and MySQL. It's too bad they made such a decision so late. I remember when open-source databases weren't too mature and was not quite suited for large enterprise application and Oracle was the DB to get. That would've been the best time for them to have made this decision since everyone wanted to try the database despite its complexity. Now, however, the complexity of running an Oracle system outweighs the advantages of using it especially when compared to using other databases that can offer the same features and performance without the difficulties of maintaining the database system.
Still, it's better late then never.