We are beginning to see the results of
Kohsuke's new job:
as of last Monday (Hudson 1.220)
Hudson includes an update center for plug-ins.
GF Update Center it tracks what
has been installed and what's available.
it can be invoked directly from within the tool.
When I fired it this afternoon I counted 66 available plugins
all installable by just checking on the tool interface.
A (clipped) screenshot of the update center page is
Kohsuke's announcement is
A (sometimes broken) track of tool and plugin downloads stats is
showing increased plugin d/ls in the last week.