Theoretically, infinite. Realistically, it's bound by the size of your storage (hard disks or solid state drives). When bliss scans your music collection, it stores information about the collection on disk.
Customers and users commonly report running with around three thousand albums. Our stress tests run bliss against nine thousand. As bliss is aimed at large music libraries, I'm always keen to hear your experiences in this regard so contact me.
Any other FAQs I forgot or clarifications required? Post your ideas below!