Andreas has been a very active tapestry user for a long time now, as well as more or less taking the lead role lately on the tacos project. I've been very impressed with his dedication to performance/browser compatibility/etc as well as his overall knowledge of javascript, which will be key with tapestry 4.1 and onward.
Besides all of these things, there is also a very real need for more day to day support of tapestry as a whole. I can't currently think of anyone (that I know) more qualified to come on board. Here are what I think his qualifications are: -) Has already been building his own components and hosting a library, long before tacos was around. (i think) http://tapfx.sourceforge.net/ The javascript portions aren't the sexiest in the world, but it's the perfect sort of background knowledge for tacos/tapestry 4.1 development. -) Has been very active in the tacos/tapestry user forms on a variety of topics. Is also more or less the current "active" lead developer on tacos. -) Googling his activities reveals that he's also done a fair amount of tacos promoting which has probably helped the project. -) Interactions with other open source projects have been very good. (specifically talking about dojo ) . Instead of the usual mailing list moaning some others are known for, I have instead found him quietly submitting patches and bug issues into their bug tracking system. I think this speaks well to his ability to represent tapestry in a professional/respectful manner. +1 (binding) jesse