Spybot-S&D Distributed Testing Client 1.6Free
The name SDDT stands for Spybot - Search & Destroy - Distributed Testing Client. SDDT was developed to be a small tool that helps improving Spybot - Search & Destroy's updates by letting your computer scan with alpha updates automatically.
Malware is growing to become more and more randomized, and one of the consequences of this is a growing risk of false positives in any anti-malware product. Just testing on more and more laboratory machines never covers the whole live situation out there though, so this is a distributed computing concept to back up the internal testing.