We describe SemEval-2017 Task 3 on Community Question Answering. This year,
we reran the four subtasks from SemEval-2016:(A) Question-Comment
Similarity,(B) Question-Question Similarity,(C) Question-External Comment
Similarity, and (D) Rerank the correct answers for a new question in Arabic,
providing all the data from 2015 and 2016 for training, and fresh data for
testing. Additionally, we added a new subtask E in order to enable
experimentation with Multi-domain Question Duplicate Detection in a
larger-scale scenario, using StackExchange subforums. A total of 23 teams
participated in the task, and submitted a total of 85 runs (36 primary and 49
contrastive) for subtasks A-D. Unfortunately, no teams participated in subtask
E. A variety of approaches and features were used by the participating systems
to address the different subtasks. The best systems achieved an official score
(MAP) of 88.43, 47.22, 15.46, and 61.16 in subtasks A, B, C, and D,
respectively. These scores are better than the baselines, especially for
subtasks A-C.

SemEval-2017 任务三关于社区问答，重新运行了 2016 年的四个子任务，提供了 2015 年和 2016 年的所有数据作为训练数据，并为测试提供了新数据，同时添加了一个新的子任务 E，以便在更大规模的情况下使用 StackExchange 子论坛进行多领域问答重复检测的实验。