Thanks Howard and Nancy! - from the article upon first scan:
...SMS and mobile IM messages seem to hold a much stricter timetable [than instant messaging]. Almost all participants indicated a punctual 5-15 minutes response time at replying to messages they receive. They expect similar response time for messages that they send out, so much so that most of them claimed that they would follow-up with a second message or phone call, if no response was given within 2 hours.
Also of note:
All participants responded that they almost always immediately notice the notification and immediately
respond by reading the SMS/mobile IM message. In contrast, participants indicated they are more likely to negotiate their response time when dealing with desktop/laptop IM messages, leading to longer delays before reading the message.
As many of you probably are aware of, here in Australia, in my state Victoria, we had some pretty horrendous bushfires (forest fires) - many lives lost, completely unprecedented fire dynamics etc. My
consultancy is providing advice and strategy to emergency services bodies regarding options for enabling smart mobs via social media, SMS and other distributed communications which got me wondering about response time.
It's interesting to think about the network effects of cascading responses, each taking 5-15 minutes - which actually adds up to sizable delays. However this doesn't take into consideration sending messages to groups, or even how many individual messages might be sent out after receiving one high priority / important message - which could create exponentially growing cascades of recipents.
Of course a major problem we had with the last fires was that mobile/cell phone coverage went down in effected areas as cell towers were consumed in the fires...