Google today announced Knol, which would appear to be their response to online knowledge repositories like Wikipedia and Mahalo:
Earlier this week, we started inviting a selected group of people to try a new, free tool that we are calling "knol", which stands for a unit of knowledge. Our goal is to encourage people who know a particular subject to write an authoritative article about it. The tool is still in development and this is just the first phase of testing. For now, using it is by invitation only. But we wanted to share with everyone the basic premises and goals behind this project.
The key idea behind the knol project is to highlight authors. Books have authors' names right on the cover, news articles have bylines, scientific articles always have authors – but somehow the web evolved without a strong standard to keep authors names highlighted. We believe that knowing who wrote what will significantly help users make better use of web content. At the heart, a knol is just a web page; we use the word "knol" as the name of the project and as an instance of an article interchangeably. It is well-organized, nicely presented, and has a distinct look and feel, but it is still just a web page. Google will provide easy-to-use tools for writing, editing, and so on, and it will provide free hosting of the content. Writers only need to write; we'll do the rest.
Link to Scott Beale's post, with pointers to some of the many online discussions around this today.