I spotted a link recently but lost it before I bookmarked it. Does anyone know what I am talking about?
It was a demonstration of a technique where you could click on a piece of text. This would then change to a textbox in its place where you could edit the text and save.

I am looking into it for an application I am working on. Does anyone know of the drawbacks of this technique.

It's an AJAX/DHTML technique conveniently called 'Edit-in-Place':

http://24ways.org/advent/edit-in-place-with-ajax

http://15daysofjquery.com/edit-in-place-with-ajax-using-jquery-javascript-library/15/