Initial experiments showed it is hard for learners to discover which posts have multiple links, largely due to the sparsity of multi-headed posts (which account for less than 5% of the total posts).
only the the most recent link for 3 http://maltparser.org/userguide.html# parsingalg 4 Classification accuracy = F-score at the thread-level, as each thread is assigned a single label of correct or incorrect.