No, it isn't necessarily useless; every day, for example, many people give their lives to Jesus Christ through the information we present on our own website (BillyGraham.org). Incidentally, many of them come from other countries, including nations that are otherwise closed to the Gospel.
At the same time, not everything concerning religion on the Internet is true, and I urge you to be cautious about using it. Almost anyone can start a website that claims to lead you to the truth -- but not all do.
In fact, many websites come from cults that promote all kinds of false beliefs, or even anti-Christian groups that deliberately want to lead you away from Jesus. Remember the Bible's warning: "I am afraid that just as Eve was deceived by the serpent's cunning, your minds may somehow be led astray from your sincere and pure devotion to Christ" (2 Corinthians 11:3).
I encourage you instead to make the Bible part of your life every day, because through its pages you'll discover God's truth. God gave it to us so that we can come to know Him and discover how He wants us to live. Most of all, through it we come to know Jesus Christ, who came down from heaven to show us God's love. Only He could say, "Anyone who has seen me has seen the Father" (John 14:9). Put your life into His hands today.