Vshare / Widdit / searchcompletion.com Adware
Vshare plugin *IS* an adware.
Whether you are on Mac, Windows or Linux this is the same, and you don’t even need the toolbar, only the plugin.
I’ve installed the old version of the Vshare plugin on my Firefox, on Linux, (old version because the newest isn’t available on Linux) then some popups started to appear on sites like wikipedia.org, loaded from some files hosted on widdit.com, and leading to search.searchcompletion.com (a quick lookup on Google shows some Windows users also see this site as their main browser page, after installing Vshare).
Widdit belongs to an Israeli company (SimplyGen), so does Vshare. Maybe both sites are from the same company.
At this point i don’t know if it only adds some random popups or also does other nasty things (like replacing ads). I didn’t read any other article on the subject, so i decided to write this post. If you have other info, post it in the comments!