Some Christian denominations believe that the baptism of the Holy Spirit is a separate experience from water baptism, often accompanied by speaking in tongues and other spiritual gifts. While some traditions emphasize confession of sins as part of the preparation for receiving the Holy Spirit, others do not.
The blog post you cited, worshipwiththetruthblogspotcom, asserts that water baptism is essential for salvation and that baptism without confessing sins is merely "water worship." This is a specific interpretation held by some within Christianity.
There are varying views on these topics within Christianity, and it is important to study different perspectives to form your own understanding.