Organizing your mail is a good way to keep your inbox uncluttered. Depending on your server, your mail can be sorted into folders and or tagged, making it easier to locate messages. (I use Gmail filters to pre-sort my mail so it is filed away when I'm done reading!)
Most services use folders. Mac Mail calls folders "mailboxes."
I think Mail is kind of a pain, and am not totally comfortable showing you around. (Not responsibly.) Here is an about.com explanation, and here is a video provided by apple. This post is almost exactly how it might turn op on Lessons for Old People so if you have questions about creating mailboxes in the Mail application, please visit it!
Ipod and Ipads have folders, not mailboxes. You can archive your mail into these folders (clicking "archive" will send the message to ALL MAIL) by moving the message into the folder desired. If you rely on these devices, click here to learn more about using the folders.
Gmail introduced labels before it "added" folders. The idea was to revolutionize the system; I think most users preferred their old habits.
Gmail has some options available to you. You can use filters to label or archive a message into a folder based on its sender or subject line. (Or a number of other factors, such as the sent-to line, attachments, and body content.) You can also drag the message to the list of labels in the left column next to your messages to apply a label.
You can also apply the label from the inbox (by clicking the checkbox next to the messages and then choosing the label from the list above your messages) or while reading the message (the label is still above the message).
Creating a label is very easy. From Google's instructions:
Here's how to create a label that you can add to any of your messages:Google still thinks of its systems as without folders. In 2009 Gmail began to allow users to "treat" labels like folders (which has allowed me to talk about folders as if they exist). The "move to" option (which looks like a folder in Gmail) will archive and label at the same time, which was, before this addition, somewhat difficult for users.
You can also create a new label for a message in your Inbox by selecting the box next to the message, clicking the Label button above your message list, and then clicking Create new.
- On the left side of the page, click More at the bottom of your labels list. (If you don't see "More," grab the gray dividing line with your cursor and drag it down to show more labels.)
- Click Create new label.
- Type the name of your new label and click Create.
If you move a message on your iPod or iPad to a folder, and use Gmail, the message will be labeled and archived in Gmail. (Just as if you clicked "move to.")
Adding folders in other clients may be more difficult. Check the help and settings of your service before proceeding.
Mac Mail basics, Apple.com
Where Mac OS X Mail Stores Mail, About.com
Mail Folder Tips, Mac Tricks and Tips
Using labels, Google support
New ways to label with "Move to" and auto-complete, Official Gmail blog
iPhone and iPod Touch: How to Use / Add Email Folders,Tech-Recipes