I collected a corpus of $n$ tweets (few thousand) during a 48-period. The tweets were all collected based on a set of search terms. The tweets were published by $a$ authors, with $a \leq n$. Let's define the collection of all tweets published by the same author as a document, the smallest unit in my corpus.
Now I want to understand if it is possible (and makes sense) to compute the distance from each document and the entire corpus. I know that the cosine similarity of term frequencies it is usually applied between documents pertaining to the same corpus (eventually weighted to account for rare words). But how to proceed if I am interested in the 'originality' of each document compared to the other fellow documents of the corpus?