Via a blog post, http://www.spatiallyadjusted.com/2010/02/07/data-gov-is-already-broken-just-like-everything-before-it/ - it would be good to integrate periodic link/service checking, ala Geospatial One Stop's Service Status Checker - http://registry.fgdc.gov/statuschecker/index.php. Any status changes/outages should be reported via notification, e.g. RSS feed / email, and directed to the stewards and registrars managing Data.gov and the respective datasets/services. This can also be tied to data management and maintenance lifecycle and associated schedules, toward automated checking that data that is supposed to be periodically maintained/updated/archived, has in fact had the requisite maintaining/updating/archival performed.
Idea No. 150