SentiWordNet is a lexical resource for opinion mining. SentiWordNet assigns to each synset of WordNet three sentiment scores: positivity, negativity, objectivity. SentiWordNet is described in details in the papers:
The current version of SentiWordNet is 3.0, which is based on WordNet 3.0
SentiWordNet is distributed under the Attribution-ShareAlike 4.0 Unported (CC BY-SA 4.0) license.
Among the other possibilities, this license allows the use of SentiWordNet in commercial applications, provided that the application mentions the use of SentiWordNet and SentiWordNet is attributed to its authors.
Micro-WordNet-Opinion 1.0 & 3.0
Micro-WordNet-Opinion 3.0 is the automatic mapping of Micro-WordNet-Opinion to WordNet 3.0, used to evaluate SentiWordNet 3.0. Download Micro-WordNet-Opinion
We run an experiment collecting users' feedback on the values assigned to synsets:
The data collection process is detailed in the report: "The User Feedback on SentiWordNet"
The collected feedback collected is distributed under a the Attribution-ShareAlike 4.0 Unported (CC BY-SA 4.0) license.