According to Google, the form does not perform a spam report or notice of copyright infringement. For now, Google just want to use the data you submit to test and improve algorithms as Google is currently testing algorithmic changes for scraper sites (especially blog scrapers).
The link to the Google scrapper form was posted on Twitter by Matt Cuts; head of the webspam team at Google.
If you see a scraper URL outranking the original source of content in Google, please tell us about it: http://t.co/WohXQmI45X
— Matt Cutts (@mattcutts) February 27, 2014
The form asks you the source URL, i.e. the original source of the content, the URL of the page stealing the content, the search results page where it is being outranked, and just a confirmation.
You can fill the Google Scrapper form here.
Such scrapper sites sometimes score higher than the original content in Google search results, thereby frustrating thousands of bloggers. So, if Google can do something about this, don't you think it will be cool??
NOTE: Use https://www.google.com/webmasters/tools/spamreport?hl=en&pli=1 to report spam or http://www.google.com/support/bin/static.py?page=ts.cs&ts=1114905 to report copyright complaints.