When Google launched GMail with 1GB of free storage, the GMail interface had neither a Delete Button nor any sort of Delete keyboard shortcut to move email messages to the trash.
Maybe, Google expected that with that kind of "infinite" storage limit, people would never want to delete email messages and instead put less-important messages in the Archives. Unfortunately, that wasn't the case, people started reaching the maximum storage limit and forced by public outcry [read, GreaseMonkey], Google did introduce a GMail Delete Button.
My biggest gripe about the GMail delete button is that it slows down the process of reading messages inside GMail. When you open a message in GMail and then delete it using the button, GMail takes you back to the folder listing. So you have again click another email to open it. There's no option to say "Move to the previous message" or "Move to the next message" when you delete an email.
Not only this, GMail provides no keyboard shortcut for delete messages or moving them to trash. There exists GMail keyboard shortcuts for almost every possible task except Delete. So you have to use the mouse pointer to delete a message, there's no way to delete in Gmail without taking the hand off your keyboard.
How to quickly read and delete messages ?
So until GMail listens and introduces Delete shortcut, here's a helpful tip for you (that's how I read my Gmail messages)
Say there are tons of unread mail in your GMail Inbox and you want to delete the useless emails after reading them once.
Step 1: Click on the Uread button to select all mail that's new or not read.
Step 2: Create and apply two GMail labels from the "More Actions" dropdown - ToBeRead, ToDelete to the mail selected in Step 1.
Step 3: Now press 'y' on your keyboard - the messages will be moved from the Inbox to the Archive folder and the respective labels folder. Don't panic.
Step 4: Click the "ToBeRead" Label under the Labels section and type 'o' - The first message opens up.
Step 5. Analyze what you would like to do with this message:
» If you like to delete it, press 'y' and then 'o' - The message is removed from the ToBeReadFolder and the next message opens up.
» If you like to keep this message in your inbox, press 'j' to open the next message.
Step 6: When you are at the last message and click 'j', the folder view will open up since there are no more messages. Choose Select All and click "Move to Inbox" from the "More Actions" dropdown. You can even say "Mark as Unread" before moving to inbox.
Step 7: Open the ToDelete Label Folder, Choose Select All and press the Delete Button. You are done!.
In writing, they may look too many steps but if you are flooded with email, this approach can save your tons of time and keystrokes. Say you had 100 messages and you wanted to delete 20 of them, this approach may have save you from reaching the mouse atleast 20 times.
Did you know ?
» After a message or conversation has been in Trash for 30 days, Gmail will permanently delete it from your account. If you'd like to permanently delete a message yourself, open the trash folder and click Delete Forever.
Should I archive or delete my Gmail messages ?
» When you're positive you won't need a message, use the Delete button to send it to Trash. If you think that you'll need a message or conversation in the future, use the Archive button.
What happens when you reach the 2 GB Inbox limit
» If you go over your storage limit, Gmail will hold your messages for a few days while you clear out some space. If you don't delete anything within that allotted time, you won't be able to receive new messages, and messages sent to your account will then be returned to sender. Here are tips to manage the size of your GMail Inbox.