The .SPB.SU domain was created for use in Saint Petersburg, Russia. It is a subdomain of the top-level domain .SU, which was established after the dissolution of the Soviet Union and registered in Russia. The .SPB.SU domain is used for websites related to the city of Saint Petersburg, its organizations, institutions, events, and culture.

Domain registration is available to any individuals or legal entities who wish to create a website with an address in this zone. The .SPB.SU domain is quite specific and can be beneficial for businesses, organizations, and individuals connected to Saint Petersburg who want to attract more local users. It can also be used to promote tourism and the city's culture.

The ".SPB.SU" domain is suitable for individuals, businesses, or organizations with connections to St. Petersburg, Russia, who want to establish an online presence with a nod to the city's history and culture. It's particularly relevant for entities operating in or targeting audiences within St. Petersburg or those seeking to showcase their affiliation with the city.