Users apparently observed the silence while sitting at their computers. Meanwhile many people around the country paused.
My experience seems a bit odd in retrospect. Having just landed in Shenzhen, a Mainland metropolis across the border from Hong Kong, I found people at the pick-up area speechless, but surrounded by blaring bus horns. I considered the possibility that the sound, which I couldn't determine the source of at the time, was an air raid siren or fire alarm. I still don't know if it was just angry drivers who wondered why traffic had stopped or a sort of alarm to mark the moment. [UPDATE: My friend Austin Ramzy writes that rescue vehicles honked in Sichuan as well.]
I spent the following week in Hong Kong, where the earthquake of course dominated the news and much discussion among foreign journalists. Now in Shanghai, acquaintances reported seeing people crowded around the television yesterday. When I got online again, I knew it was the newest aftershock.
Television seems to be dominated by hopeful stories. Record rescues, hard-working soldiers sifting through rubble, national leaders consoling and rallying earthquake victims. Foreign media on the other hand broadcasts its usual extremely sad images. Mothers digging through concrete slabs looking for children, sons wearing lost fathers' clothing.
A three-day period of mourning last week was marked online by the temporary shutting of several entertainment websites, including Tudou, and myriad commemorative displays.
Whether people here know anyone in the affected areas or not, the national character of this ongoing loss of life is impossible to avoid.