Four short links: 27 July 2009

1. Ignite OSCON -- 56m of video from Ignite OSCON. They're all great, but Dan Meyer remains the highlight for me.
2. gheat -- a maptile server in Python, delivering heatmaps to be superimposed on Google Maps. Handy for visualization fiends.
3. CaDNAno -- open source software for design of 3-dimensional DNA origami. One of George Church's projects. I love the combination of math, biology, and whimsy in open-source giftwrap. (via timoreilly on Twitter)
4. CommentPress -- an open source theme for the WordPress blogging engine that allows readers to comment paragraph by paragraph in the margins of a text. Annotate, gloss, workshop, debate: with CommentPress you can do all of these things on a finer-grained level, turning a document into a conversation. It can be applied to a fixed document (paper/essay/book etc.) or to a running blog. I'm taking a greater interest in tools that channel and focus participation rather than simply providing "edit this page". (via gov2.net.au's issues paper)