I believe the old Webroot products used Sophos, but this is 100% inherited from Prevx as far as I'm aware.
I will confirm, the old version used the Sophos engine for AV and the Webroot engine for AS. SecureAnywhere uses technology built from Prevx by the Prevx peeps, not a lick of Sophos.
I'm surprised trjam is asking this now as it's been known for ages WSA uses Prevx technology. The older Webroot products did use the Sophos engine. That was the whole point of the buyout of Prevx in my opinion: to ditch Sophos for their technology.
The previous posters are correct - the old Webroot products used Sophos but WSA does not use it at all: it is the completely in-house built Prevx/WSA cloud-based detection.
Yup...it is 100% Prevx technology. So much it should say it somewhere in small print just to look cool and give honor to Prevx The exception is I think Joe said they added Webroot's spyware definitions to the cloud basically. Other than that the antivirus aspect is all Prevx as is ID shield. Now, the other stuff like the system cleaner, firewall, etc., I am assuming is Prevx as well as you guys designed that for P4 originally, right? So the only other thing that is Webroot technology pre-Prevx era specifically is the Backup & Sync (optional module)?
I think the System Cleaner is a stripped down version of what was available in Webroot Window Washer so I don't think that's entirely a Prevx innovation. Bacup & Sync is licenced from Sugarsync. The only other thing you didn't mention is Password Management; that is based on the LastPass product and uses their technology. Both these were available in earlier versions of Webroot security products.