Online document collaboration has definitely changed the way how people share and edit documents, which more than one person being able to access and make changes to the same document, this feature is pretty popular in Google Docs.

However the collaboration feature in Google Docs is not real time and it takes almost 10-15 seconds for a change made by one person to reflect on the other active collaborators documents. EtherPad is a service that provides users with real-time collaboration for editing plain text documents.

EtherPad lets you collaborate and edit text documents between more than one authors, making it easier to track which author is making changes, by highlighting the changes in a different color. EtherPad is not a document collaborator and does not support rich text editing, so you will have a experience of collaborating a notepad file.

Here is a quick comparison between Google Docs and EtherPad:

• Google Docs are cumbersome to share with other people. It requires sending an email, and all collaborators must have a Google Docs account. With EtherPad, you just copy and paste a link, no emails or accounts required.
• Google Docs does not highlight who typed what, so with more than 2 editors, things get chaotic and confusing very quickly. EtherPad makes things clear by highlighting each author’s contributions with a unique background color.
• One of the most basic operators for editing text is "undo." In Google Docs, while collaborating, you lose undo history whenever someone else makes a change. EtherPad supports infinite undos and ensures that every operation is forever undo-able, even in the presence of other editors.

Though EtherPad has several features which Google Docs lacks, they could be added by the Docs team in near future.

EtherPad [via tweet from Gaurav Gupta]