Application folder naming convention I was just wondering why the naming of some folders on android is such:

com.dropbox.android
com.android.browser
Further to answer from @PratapPatil who has given the Android details.
This is a convention in programming, specifically here Java.
The Java Tutorials package details give details and examples.
With programmers worldwide writing classes and interfaces using the Java programming language, it is likely that many programmers will use the same name for different types. In fact, the previous example does just that: It defines a Rectangle class when there is already a Rectangle class in the java.awt package. Still, the compiler allows both classes to have the same name if they are in different packages. The fully qualified name of each Rectangle class includes the package name. That is, the fully qualified name of the Rectangle class in the graphics package is graphics.Rectangle, and the fully qualified name of the Rectangle class in the java.awt package is java.awt.Rectangle.
This works well unless two independent programmers use the same name for their packages. What prevents this problem? Convention.
Naming Conventions

Package names are written in all lower case to avoid conflict with the names of classes or interfaces.
Companies use their reversed Internet domain name to begin their package names—for example, com.example.mypackage for a package named mypackage created by a programmer at example.com.
Name collisions that occur within a single company need to be handled by convention within that company, perhaps by including the region or the project name after the company name (for example, com.example.region.mypackage).

For an alterative angle on this the StackOverflow quesion is around naming a hobby project.  The naming could be something like rossc.android.exampleproject  since I don't have a domain of my own.