zaps represent value
in the beginning, people zapped for fun, for thrill, to be cool and with it. even if the note itself has no content value, the value came from "ooo cool, look at what I can do" which is fine and legitimate.
now that the novelty has worn off, people are consciously choosing to zap notes that they find valuable. zaps are still flying when people come across notes that are interesting, informative, provocative, and/or creative.
Bottom line, if you're not getting zapped anymore, that means you're not contributing to the community in a way that others find valuable. Change it up. People are more different now and aren't handing them out for funsies anymore.