You could write games and the like in Visual Basic, but I wouldn't recommend it. You give up a lot of low level control and speed by using Visual Basic.
You can write HTML editors in Visual Basic, but not webpages. You could write ISAPI DLLs for use with IIS, and perhaps Apache on win32. Other than that though, I don't think Visual Basic itself is much good for the web.
Another problem with Visual Basic is that you are locked into pretty much one platform. If you learn C++, you can code for anything, but Visual basic is going to limit you to Windows and Mac platforms (assuming MS is still making Visual Studio for Mac).