Just came across my blog post from 6 March 2009 that reads: " Fad maybe, but over 90 people are now following Total Telecom on Twitter".
I'd added a note on 5 May that said now 377 followers. Unfortunately I didn't continue with the updates but now @totaltelecom is at 6,851 followers. Wonder if that's still a fad?
Doesn't quite rank amongst the greatest failed predictions of all time though - but here's a better list "Ten Failed Technology Predictions" from the blog Skeptoid - I especially like "There is no reason anyone would want a computer in their home"