This natty little symbol can serve as a method for searching, and categorising from a myriad of sources, materials on a particular topic. On Twitter, this serves to both allow tracking of discussion of certain subjects, and for the tuitero saves explaining the context of remarks (crucial in a space where the number of characters available is limited). It makes it possible to enter into broader discussion, but also allows for many jokes and tweet memes (such as #threewordsaftersex). The # can also serve to explain feelings – in an absence of conversational tone, they expand on the utility of emoticons. In this sense, the use is not about joining a thread of comments on a topic, but expressing the author’s relationship to the situation described. Examples are #happynow #forcryingoutloud. This is also an opportunity for wry humour or sarcasm. They also allow for the briefest of commentary on quoted material, public topics or figures. It is this (often ironic) use which allows the author to subvert the text of another or add commentary in the form of a single word. If I quote a public figure and add #idiot – I don’t need to explain that I am making this comment. This ability to add editorial labelling is something I have been considering with regard to academic research. Blogs have long used tags – most often to search within a single blog. These tags are also added by the original poster: reflecting what they think the topic or theme is (often with idiosyncratic subject headings), not any external commentary. The use of tags or keywords in research notes is also common: I use Bookends for my bibliographic notes, and I am sure that other digital humanists have already incorporated # into their files. But it only recently occurred to me that I could use them as a point of commentary, as in Twitter. Rather than simply classify a work by keywords such as “urban”, “architecture”, “housing” (as I do now), to add such # as #helpful, #withtables, or #outdated, #unclear, #boring. Could such tags also be used in articles some day? A way of summarising historiography without lengthy discursion. Would shortening articles in this way have any appeal?