Should Bernie make more "calls for action" during his speeches?

After seeing the large turnout in SC, it made me think about how many of those people would go out and phonebank or canvas for Sanders. I don't think the number is very high, sadly. Maybe if, at the end of his speeches, he asked for people to volunteer and help out it would encourage more people to do it.

I feel like we are at a point now that most of the people that go to his speeches are already supporters (mostly) but haven't made the switch over to volunteering yet. Every time he makes a mention of something directly, whatever it is seems to spike. For example when he mentioned donations after (was it Iowa or New Hampshire?) and then he had the largest donation day so far. When he tweeted the "iwilllookintoit.com" site, everyone crashed it from heavy traffic.