This study provides a systematic investigation of party and candidate websites across five countries. It examines three prominent features of current online political communication (interactivity, political personalization, and mobilization). Furthermore it assesses to what extent country, party, and source characteristics explain differences in the usage of these features. In total, 63 websites and 416 pages in Germany, Romania, Hungary, the Netherlands, and Great Britain were subject to a systematic content analysis. The findings suggest that differences in party and source characteristics explain variation in levels of mobilization, interactivity, and personalization, with, for example, party websites trying to mobilize citizens while websites belonging to politicians are used as a platform for self-promotion. In general, results show that the division of countries into East and West European is less important.