Widgets are relatively small programs designed to work on your computer's desktop or in conjunction with blogs and social networking pages. One of the major widget makers has over 9 billion (that is with a "b") impressions a month. As a side note, that really puts whatever I do on the Web into perspective. I did not make a link to their Website because I found it objectionable.
Two of the more popular widget makers are are Widgetbox and Clearsping, both of which seem to have been used for more useful, as opposed to entertaining, widgets. The widget makers advertise for you to create, distribute, track and monetize widgets. Clearspring also advertises distributing your content as "viral widgets."
A search on Widgetbox on the term "genealogy" brings up dozens of widgets dedicated to genealogy. Looking at a sample of the widgets shows that most have only a few installs, but some have over 100.
It is hard to tell who is sponsoring these genealogy widgets, but it appears that most of them, presently, are from private individuals. Some of the developers, seem to be using the genealogy tie-in to promote other causes, some of which might be found by some to be objectionable. As in any online viewing, caution is required to avoid bad content.
It is likely that we will see widgets everywhere on the Web, even more than we do now, in the immediate future.