Update (2015-09-29): Various improvements!
Please let me know if any of these changes are causing problems or not working as expected.
The given page doesn't seem to exist: Allan McLean (philanthropist), McLean's Mansion.
This tool attempts to detect copyright violations in articles. In search mode, it will check for similar content elsewhere on the web using Yahoo! BOSS and/or external links present in the text of the page, depending on which options are selected. In comparison mode, the tool will skip the searching step and display a report comparing the article to the given webpage, like the Duplication Detector.
Running a full check can take up to 45 seconds if other websites are slow. Please be patient. If you get a timeout, wait a moment and refresh the page.
Specific websites can be skipped (for example, if their content is in the public domain) by being added to the excluded URL list.