It was working, just not enough relative to all the capital they raised. The marketplace was growing 8% month over month, since forever. They wanted faster growth but couldn't get it, so pivoted.
It seems like they were running about $500K a year. Even with 100% growth per year, it's going to take 6 years to begin moving $40 million annual revenue. The investors aren't going to wait for that long. And, as people have pointed out, once I use TaskRabbit, why don't I contact the task person directly next time?
Attempts to quantify TaskRabbit's numbers: http://www.quora.com/How-much-revenue-is-Taskrabbit-com-maki...