{{wi}} is a handly little shortcut that equates the following markup:
''[[wikipedia:article name]]'' --> {{wi|article name}}
In other words, it's the same thing as {{w}} except that it adds italics automatically. Think of it as wikipedia italics, or wi. It's thus a tool that makes following T:ITAL that little bit easier.
Usage
{{wi}} incorporates one kind of pipe trick. As long as the wikipedia article is not disambiguated, then it will automatically get rid of the prepending "wikipedia:". Hence,
{{wi|The Way We Were}}results in The Way We Were.
However, if the wikipedia title is disambiguated, you must type a little more. For instance,
{{wi|Casablanca (film)}}renders the undesirable Casablanca (film)- but
{{wi|Casablanca (film)|Casablanca}}renders a title on wikipedia in the italicised the way we want: Casablanca