Ask the designer/see the maemo-community archives.

(FWIW, I don't think there's a "rationale" been put forward for the colour choices. The orange features in the maemo.org logo, and carrying it through the rest of the site was, presumably, seen as an attempt to have a unifying brand/simple colour scheme)

I would be interested to know if anybody had a general suggestion for the colour of links in the body text which fit with the rest of the theme.