Widgets or Gadgets are the new evolvement of the Web 2.0, of course again, not many people understand their meaning. I of course also cannot give an absolute answer, however, since Mar., I have been working on a Flash based widget myself, and I have this definition. Widgets or Gadgets are the mini applications which can call the web services through different interfaces. The through different interfaces part were added after my colleagues are talking to me about their fantasy on widgets and Nokia people told me about the widgets on nokia phones.

Afterall, widgets are not standard, and probably it would be standard in flash, that <embed> tag. However, from Widsets (www.widsets.com) and Javascripts, DOM2, XHTML, all are depending on a specific hard code for the interface. From W3C, there are people talking about something like widget protocol (http://www.w3.org/TR/widgets/), but it is mainly for narration purpose. The function and process of which to call the web service are not defined.

I would give an advise to a widget developer, try to stick with HTML and XML (or SOAP if you want), since no matter how the widget would be (flash or J2ME), those callable functions at the server side would still be reusable. Of course, flash would be a good start for people to put your widget to various portals. However, you have to be an Actionscripts literate to write a true widget. HTML is already not enough for this world.