Spywareblaster is a passive app mta in that it doesn't run in the background, all you need to do is manually update it a couple of times a month. It is not a traditional av or malware app, it is another layer of protection with a slightly different twist to others. You can run it alongside almost anything as there are no services etc involved.
A couple of quotes here form Bleeping computer may give you a better idea of how it works.
# Prevent the installation of ActiveX-based spyware, adware, browser hijackers, dialers, and other potentially unwanted software.
# Block spyware/tracking cookies in Internet Explorer and Mozilla/Firefox.
# Restrict the actions of potentially unwanted sites in Internet Explorer.
More techie..
SpywareBlaster adds sites to the restricted zones by adding the domain as a subkey under the registry key: HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap\Domains. A dword is then added to that domain named * and given a hex value of 4 to specify that it is part of the Restricted Sites Zone. More specifically, Spywareblaster sets the "killbit" on the CLSID's of known spyware. Every program has a CLass ID that is unique to the type of program. Once Spywareblaster enables (writes) those killbits they are "locked in" and any identified spyware cannot be opened. Spywareblaster writes these killbits in and then stays off until you need to re-write them again with an update.
SB does not run in the background. Instead it only requires installation and then enabling of all protection. After that you only have to check periodically for database updates and then enable all protection again.
I have this foggy memory somewhere that, back in the days when Spybot S&D came out (and that one I loved) there were others that were just plain bad.
they weren't a fix, they just got rid of the competition and made themselves king of the adware/spyware heap instead.
It obviously wasn't spywareblaster, but something similarly named, so I guess between Spybot and MWB (which I replaced it with) I haven't gone looking/needed more protection.
Probably because the restricted zones that it writes to and 'the killbits'' (great word) have no ability or need to tell you 'hey something tried to open me'
I've always looked on Spwareblaster as a bouncer on the door of my PC. It checks that you're on the allowed in list.
Edit: FWIW, there was a period of time several years ago when SpywareBlaster and Spybot S&D had small conflicts.
Each kept turning off a small part of the others functionality.
Don't remember the details, have not used S&D for a while, but i don't think it is an issue nowadays.
Had to do with either restricted sites or cookies in Internet Explorer, I also remember that and eventually dumped Spybot-S&D because of it and have never looked back.