The provided URLs and LinkedIn link do not offer specific details about "ONE House" at http://www.one-house.pl. However, based on typical company profiles, it is likely that ONE House could be involved in real estate, construction, or home services. Without specific information, it's challenging to define their services or target audience. If they are in real estate, their unique selling proposition might involve offering personalized housing solutions or innovative property management services. For precise details, visiting their website or contacting them directly would be necessary.