Other possibilities, not all necessarily ‘rationalist’:
http://www.acceleratingfuture.com/michael/blog/http://felicifia.org/http://www.utilitarian-essays.com/http://naturalism.org/http://www.infidels.org/
Most of those are in the queue now. (I think linkchecker crashed somewhere spidering the latter 5, so I’m not sure how complete coverage is.)
Other possibilities, not all necessarily ‘rationalist’:
http://www.acceleratingfuture.com/michael/blog/
http://felicifia.org/
http://www.utilitarian-essays.com/
http://naturalism.org/
http://www.infidels.org/
Most of those are in the queue now. (I think linkchecker crashed somewhere spidering the latter 5, so I’m not sure how complete coverage is.)