The Inline abuse report web part allows live site users to report various forms of website abuse. These can be for example flame-type forum posts, rude comments on blog posts or message boards, spamming, links to illegal content or any other form of website abuse coming from user input. Reporting is performed by clicking the link, which opens a dialog where the report text can be entered into a text field and submitted by clicking Report abuse.
Submitted reports are linked to the page where the web part is placed and can be viewed and managed in the administration interface through the Abuse report application.
You can find full documentation in Abuse reports.