I'm running Windows 7 with IE11 and Spybot updates from 4/24. I got the following entry in a recent scan:

PornoAssist: [SBI $6749D087] User settings (Registry key, nothing done)
HKEY_USERS\S-1-5-21-830593641-2385924060-362116996-1001\Software\Microsoft\Internet Explorer\DOMStorage\addthis.com

Aside from tracking cookies, no other items were detected. I chose "fix selected problems," which deleted the registry key. After re-scanning, no issues were detected.

The referenced registry key appeared valid. It contained two values, NumberOfSubdomains and Total. If I visit addthis.com (which is a valid commercial website), it's recreated and subsequently picked up by in a Spybot scan, which seems to confirm it's a false positive.