Abstract: A method and arrangement in a segmentation manager (200, 600) for forming segments of customers in a communications network for use when offering services to customers jointly in those segments. In the segmentation manager, data relating to the customers' service usage and websites browsed by the customers is collected (500) and subject domains associated to the browsed websites are identified (502). A browsing behaviour of each customer is also determined (504) based on their browsed websites and associated subject domains, and domain interests of each customer are determined (506) based on their browsing behaviour. At least one customer segment is then assigned (508) to each customer based on his/her service usage and domain interests.