Participatory Budgeting (PB) is an yearly deliberative process for citizens to decide directly over the public expenditures. It was born in 1989 in Porto Alegre, Brazil, and awarded in 1996 by the United Nations as one of the world's best practices of local governance. ICTs have been used to support PB initiatives and increase citizens participation. However, the so called Digital Participatory Budgeting (DPB) so far mainly focused to share information on the ongoing process and to carry on the voting phase. The paper outlines the evolution of BiPart, a software platform designed for accompanying the overall PB process, and strengthening the social ties. It also presents its application in seven instances of PB in four municipalities in Italy along five years, to test its actual use and its impact on citizens' participation.