namespace naming conventions

For those of you out there writing reusable components, what do you consider to be best practice if you're extending the functionality of the .NET framework?

For example, I'm creating a Pop3 library at the moment as one doesn't exist in .NET. Do I create a custom namespace or do I use System.Net.Mail ?

From the Namespace Naming Guidelines:

> The general rule for naming namespaces > is to use the company name followed by > the technology name and optionally the > feature and design as follows. Copy > Code > > CompanyName.TechnologyName[.Feature][.Design]

Generally it's a really bad practice to start including things into the default namespace of a framework or library. This can cause confusion in terms of whether a new namespace is part of the existing library that is part of a framework that is distributed to everyone, or is part of a custom framework that was added by someone else.

Also, the naming convention tries to avoid namespace collisions by having unique identifiers such as CompanyName. It also reduces any confusion and issues in terms of the source of the new library.

This is not only a Microsoft thing, but in the Java as well. Namespaces in Java, called "packages" has the following convention:

> The prefix of a unique package name is > always written in all-lowercase ASCII > letters and should be one of the > top-level domain names, currently com, > edu, gov, mil, net, org, or one of the > English two-letter codes identifying > countries as specified in ISO Standard > 3166, 1981. > > Subsequent components of the package > name vary according to an > organization's own internal naming > conventions. Such conventions might > specify that certain directory name > components be division, department, > project, machine, or login names.

So, if I had a super awesome piece of software, it may be in the net.coobird.superawesomesoftware package.

And using package names that contain the default java., javax., com.sun. packages are a big no-no.

Also have a look at following MSDN article for guidelines about naming Namespaces

> Names of Namespaces > > The name chosen for a namespace should indicate the functionality made > available by types in the namespace. For example, the > System.Net.Sockets namespace contains types that enable developers to > use sockets to communicate over networks. > > The general format for a namespace name is as follows: > > <Company>.(<Product>|<Technology>)[.<Feature>][.<Subnamespace>] > > For example, Microsoft.WindowsMobile.DirectX.