Google Wave Extensions Gallery was rolled out today, in hopes to make it easier for users to discover and utilize the extensions that developers have been building on the real-time based collaboration platform. Google Wave got se

rious attention when it was first released, but invite-only access and limited usability slowed the spread of usage quickly.

The gallery contains extension installers which are visualized as puzzle pieces on the Wave navigation bar. To use an extension, the user must first install it, and it then appears as an icon in the editing toolbar or adds a drop-down area to the "New Wave" menu.

At this writing there are eighteen available extensions, including Sudoku, a Yellow Highlighter, Goo-gly URL shortener, gadgets for entering images and polls, and lot of other little games and creativity encouragers/time-wasters.

This trails the release of Robots API v2, a part of the Google Wave API announced on Tuesday, that gives developers tools that can push information into waves without relying on a user's action, such as when the weather changes or a stock price falls. The tools, or robots, as they are referred to in the Google Wave developer blog, can be also be deployed based on context, filtering, error-reporting or by proxy from another non-Wave system.

Google Wave has too limited a user base for any marketing strategy to exist in earnest. It is possible that it may never be a stand-alone platform in the manner that Twitter became. Whether it does or not, the usability that is currently being developed for it can definitely be useful for brands.

The Take-Out Gadget extension, for example, currently lets a group of people in an office, classroom or dorm plan an order together. It also has a timer so that people know how much longer they have to make up their mind. This extension could easily be connected to corporate Wave account holders, so that the group connects with a restaurant in a Wave, and know what items are sold out, or a daily special.