how to deal with web plugin when first time running unity?

Hi,
I got one question here, when I first run one unity web game(jumpstart) on one machine, I got noticed that unity web plugin need be installed onto my machine. I am wonderring who did the offering web plugin job? the unity or the jumpstart?

Now I am going to let some other guy to play unity web game developed by me, so I also need to consider this question. If the game developer need to offer the web plugin, then how to accomplish it?

Thanks in advance if someone can help me on this:)

the plugin must only be distributed through UT, nobody else is allowed to.

If you just use the build web feature, you get a html along your unity3d file, which takes care to inform the user that needs to download the plugin including the required link.

got it, thanks:)