From Seo Wiki - Search Engine Optimization and Programming Languages
Google Labs is a website demonstrating new Google projects "that aren't quite ready for prime time". It serves as a testing ground for new services being developed. This is a way for Google to gain feedback on the products before releasing the final versions. Google's services do not always appear on the Labs page; some are beta tested by invitation-only, like Gmail and Google Calendar once were, and Google Wave still is.
In 2006, all Google Labs products had a consistent logo, using the flask, and a gray title, as opposed to other color-coded Google products, such as Google News and Google Maps. This warns users that the product may contain bugs, and could be unfit for general use.