Google suffers another outage

Archived discussions on all Google Groups were unavailable for a short time this afternoon. Any attempt to view messages was greeted with this error:

All groups were affected, for example the Android Developers group, the H2 Database group, and even Usenet groups like misc.invest.technical.

The cause and duration of the outage is unknown. Update: As of this writing, access has been restored and the system appears to be working normally.

This latest outage follows on the heels of a 4 hour GMail outage last week, and an infamous outage in January that caused all web sites to be reported as sources of malware. Sam Diaz says these outages are "not deal-breakers", but how many of them will it take to become a problem?