Gmail (

) is down for some users tonight, based on our own issues with the service today, numerous complaints from friends and hundreds of reports on Twitter (

). The most common error appears to be “503 Service Unavailable”.

Gmail downtime is frequently remarked upon on blogs and social networking sites. As Gmail speeds ahead, adding features like Inbox Preview today (preview your inbox before it loads fully on a slow connection) and the addition of Google Translate this week, it’s tempting to claim that the basics – keeping Gmail online – are somewhat lacking.

That situation, if real, would undermine the case for “the cloud” – the idea that Google (

) and other web services will steal market share from Microsoft and desktop apps by hosting all your services online. And yet Google put forward stats last year showing that Gmail has significantly better uptime than Exchange and Lotus.

Why, then, the outcry whenever Gmail is down? Could it be that Gmail users are simply better connected online, and have more outlets through which to vent their frustrations?