BPOS, a collaboration and communications suite hosted by Microsoft and sold with partners, includes Exchange Online, SharePoint Online, Office Communications Online and Live Meeting.
Last week, in 2010, for both individual account holders and people who use it as part of Google Apps, a BPOS rival. Google didn't provide the uptime rate for the other Apps suite components, like Docs and Calendar.
Google and Microsoft offer a 99.9 percent uptime guarantee for their Apps and BPOS suites, respectively. When that service level agreement (SLA) isn't met, Google offers affected customers credits and extends their subscriptions, while Microsoft offers cash reimbursement.
Google announced last week that it was modifying its SLA to count every instance of downtime; previously, it logged only outages of 10 minutes or more. It also tweaked its SLA to include outages due to planned maintenance work, which previously wasn't counted against the 99.9 percent uptime commitment.
According to a spokesman for Microsoft, the BPOS SLA counts "any service issue as downtime, from the minute it starts to resolution."