You receive a message in Gmail's inbox and after sending a reply, Gmail shows your conversation and a list of options: "back to Inbox", "Archive", "Report spam", "Delete", "Older" and more actions. Most of them don't make any sense in this specific context, but they're kept for consistency. You'll probably go back to the inbox and read the next message, but if you like to have a clean inbox you'll also archive the message you've just replied to.
A new feature available in Gmail Labs lets you automatically archive a message after sending a reply. The default button becomes "Send & Archive" and it will perform the following actions:
* send the message
* archive the conversation
* go back to inbox
"More often than not, as I reply to a message I also want to archive it so I can enjoy the satisfaction of a pristine inbox. Having clicked "Send" followed by "Archive" a few million times, I started to wish there was a way to just click once and accomplish both actions at the same time," explains Pal Takacsi, who added the small new feature.
Another multi-action button that would make many people happy could combine labeling conversations and archiving them. What other smart buttons would you like to see?