Spring MVC: difference between <context:component-scan> and <annotation-driven /> tags?

Some days ago I began to study this Spring Hello World Tutorial: http://viralpatel.net/blogs/spring-3-mvc-create-hello-world-application-spring-3-mvc/

In this tutorial Spring DispatcherServlet is configured using the spring-servlet.xml file, this one:

<?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:p="http://www.springframework.org/schema/p"
    xmlns:context="http://www.springframework.org/schema/context"

xsi:schemaLocation="
    http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/context 
    http://www.springframework.org/schema/context/spring-context.xsd">

<context:component-scan base-package="net.viralpatel.spring3.controller" />

<bean id="viewResolver"
    class="org.springframework.web.servlet.view.UrlBasedViewResolver">
    <property name="viewClass"
        value="org.springframework.web.servlet.view.JstlView" />
    <property name="prefix" value="/WEB-INF/jsp/" />
    <property name="suffix" value=".jsp" />
</bean>

In this file I am using the context:component-scan tag to say that Spring have to scan my file searching the annotation, so for example, when the controller class finds that a method is annotated by @RequestMapping("/hello") annotation knows that this method handles the HTTP Request toward the URL ending with "/hello". This is simple...

Now my doubt is related to the Spring MVC template project that I could automatically build in STS\Eclipse.

When I create a new Spring MVC project in STS I have that my DispatcherServlet is configured by a file