It seems to me that this is going to be a bit like the Pipes tool from Yahoo, except instead of a data mashup coming out of the combination of multiple services you will instead have some kind of "action" taking place.
From the article: "For instance, you can use Google reader starred items to share images on your Tumblr blog, or customize how and which photos from your Flickr stream show up on your Facebook wall."
So, I guess that ifttt will allow you to define workflows such as:
IF "I star a Google Reader item" THEN "post it to my Tumblr blog"
I can actually see this kind of thing being useful to some people.
Edit: They actually have a WTF page which says what I just said: http://ifttt.com/wtf