A bug introduced during a routing system update caused Gmail to turn some users into unintentional spammers by resending some messages multiple times.
The problem started on 19 August and was fixed on 25 August. In the meantime, frazzled Gmail users vented their frustration at the Gmail Help Forum, clamouring for Google to implement a fix and spare them the embarrassment of coming across as careless and obnoxious pseudo-spammers.
"We appreciate your patience and again apologise for the impact to your organisation," reads an incident report Google posted on Tuesday. On the plus side, the bug caused no performance problems, delays or message failures.
Google is pledging to sharpen its monitoring of mail flow after implementing a system update, as well as to proactively test to ensure message duplication isn't occurring, according to the report.
The bug affected no more than 2.5 percent of Gmail users, of which Google says there are "hundreds of millions", so the number of Gmail users hit likely ranged from hundreds of thousands to several million, not counting the impacted recipients. At the time, Google declined to be more specific about the number of affected users.
Gmail is a free service for individuals and also the email component of the hosted Google Apps suite, which has free and fee-based versions designed for workplace use.
With Google Apps, Google has become a major proponent of cloud computing, and specifically of enterprise software-as-a-service (SaaS), where vendors host their software products in their own data centres and customers access the applications and data via the internet.
More and more businesses find this model attractive, because it lets them save on hardware and shifts the often tedious and time-consuming task of software maintenance to the vendor.
However, when something breaks on the vendor's end, IT managers find themselves in the frequently helpless and stressful position of fielding complaints from their users without being able to do much to remedy the situation.
In these incidents, Google is far from alone, as they strike pretty much all providers of hosted software, making the concern over this issue a generalised one and very much on the table when the pros and cons of the SaaS model are discussed and debated.