This reminds me of the different approaches taken to Widgets/Gadgets. Last
time I was on the Yahoo Gadget site they were inviting me to download their
widgets, there were three logos, OSX, WIN and Linux, a widget for each OS.
No wonder Yahoo are a failing company. Google invite users to embed widgets
in their own page. I suppose this is the client - server argument again.
As a developer I would far prefer to embed different searches in web pages
than offer visitors a plugin no matter how good an icon file I could come
up with.
Having said that I use the Wikipedia plugin all the time, though that's the
only one I do use apart from Google. I can't see that changing but you never
know.