Got a great response to last week's frequently asked questions about Google Wave, and it's worth expanding further on the differences between Wave and the current crop of web-based collaboration offerings.
Wave combines features from email, instant messenger, Google Docs, wikis, and forums and throws its own spin on things. For a quick visual of its offerings versus similar tools, check out this feature-by-feature comparison.
|Feature||Instant Messenger||Google Docs||Wikis||Forums||Wave|
|A single, hosted copy of a conversation or document||No||Not usually||Yes||Yes||Yes||Yes|
|The ability to see when contacts are online||No||Yes||Yes||No||No||Yes|
|Instant messaging or chat, with no-refresh updates||No||Yes||Yes||No||No||Yes|
|Keystroke-by-keystroke live updates with multiple visible cursors||No||Some services||No||No||No||Yes|
|Simultaneous editing of one document by multiple collaborators||No||No||Yes||Yes||No||Yes|
|Edit rights to other participants' contributions||No||No||Yes||Yes||No||Yes|
|The ability to see, compare, and restore past versions||No||No||Yes||Yes||No||Yes|
|Interactive maps, videos, polls and other widgets||Not really||No||Some||Some||No||Yes|
|Inline replies and threaded conversations||Manually||No||No||No||Some||Yes|
|Ability to easily publish the conversation or document||No||No||Yes||Yes||No||To other Wave users|
|User access permissions (read-only or edit)||N/A||N/A||Yes||Some||N/A||Yes|
|Ability to easily link documents to each other||No||No||No||Yes||No||Yes|
|Ability to export the finished document to a file||No||No||Yes||Manually||No||No|
You'll notice that Wave doesn't have a green yes in every cell in its column; it's still missing functionality that's holding it back from being a viable alternative in a production environment--specifically, user permissions (everyone can edit everything) and the ability to export a wave or publish it so that anyone can see its contents (not just folks logged into Wave).
This table is slated to go into chapter 1 of the first edition of The Complete Guide to Google Wave, so give me a shout if you've got ideas for how to polish it up before we boot up the printers.
Update, January 21st: Changed Wave's user access permissions column to reflect the newly-announced feature.