WolframAlpha Widgets are mini applications built on Wolfram Alpha queries. You can share them in several ways – Facebook and Twitter for example or embed them in a blog or website. Either use a widget from the growing gallery (note the categories on the right) – see Mathematics here or create your own.
See Wolfram Alpha’s own blog entry.
For further information on WolframAlpha these links may be useful:
WolframAlpha YouTube Channel
10 questions younger children could try – Wolfram Alpha Blog entry