5. The method of claim 1 , wherein receiving, from a user computing device, the one or more content items comprises: causing a set of candidate content items to be displayed at the user computing device; and receiving a selection of one or more of the candidate content items.
6. The method of claim 5 , further comprising: determining a position of each of the selected contents items on the graphical representation, wherein causing a graphical representation of the structural document to be displayed at the user computing device comprises causing the selected content items to be displayed at the corresponding position of the graphical representation.