Web of Trust has come under scrutiny of German television channel NDR (Norddeutscher Rundfunk) which has found that the app has been collecting data of its users and selling the data.

The station found that WOT did not anonymize the data correctly so that it is easy to expose your real identity and every detail about you.
What kind of data did the station find when it looked at 50 users:
• Account name
• Mailing address
• Shopping habits
• Travel plans
• Possible illnesses
• Sexual preferences
• Drug consumption
• Confidential company information
• Ongoing police investigations
• Browser surfing activity including all sites visited

This was a sampling of 50, whereas WOT has more than 140 Million users.
In response to this article, Mozilla has already remove WOT from its Firefox Add-ons page. WOT removed it from the Chrome as on page.
In a statement, WOT said "we take our obligations to you very seriously. While we deployed great effort to remove any data that could be used to identify individual users, it appears that in some cases such identification remained possible, albeit for what may be a very small number of WOT users," claiming that they are taking these steps:

• Reviewing our privacy policy to determine which changes need to be made to enhance and ensure that our users' privacy rights are properly addressed.
• For the user browsing data used to enable WOT website reputation service, we intend to provide users the ability to opt-out of having such data saved in our database or shared. This opt-out will be available from the settings menu, as we want to provide each user with a clear choice at all times.
• For people who agree to let us use their browsing data to support WOT, we will implement a complete overhaul of our data 'cleaning' process, to optimize our data anonymization and aggregation objectives to minimize any risk of exposure for our users.

Anyone using the extension is advised to remove it.

Source: The Hacker News