Maybe these use SpamAssassin
The following might use SpamAssassin. It has been suggested that they use SpamAssassin, but their public websites do not give any indication either way.) Other versions: CommercialWindows, CommercialMacOSX, CommercialUnix, CommercialNetworkAppliances, CommercialISPs, CommercialMaybe
Bastion Mail relay service based on Spam Assassin and Mail Scanner.
If your commercial product uses SpamAssassin, and is not listed here, please feel free to edit the page and add details. However, keep it short -- preferably just a link -- and we reserve the right to edit or even remove whatever's published here (especially if we cannot determine from publically-accessible information that the product does use SpamAssassin).
For fairness, we're trying to keep the items in each category in alphabetical order.