> Now we have a small but proper sales team. However word of mouth got us very, very far.

Note that viral is not the same thing as word of mouth. Viral means that one user expressly or subliminally forces other users to use that software.

For example, a customer asking or encouraging a vendor to use some specific software because it makes things easier for the customer and later, when that vendor is also infected with the need, they ask or encourage their own vendors to use that software too.

This is the distribution mechanism that we have for our tool.