Members of Parliament (MPs) mobilize on social media platforms to pursue individual and party goals. Social media is a political venue in which MPs increasingly mobilize to maximize their chances to get reelected, getting into leadership positions, and pursuing policy goals. Several studies have analyzed which MPs are more likely to be active on Twitter, how frequently they tweet, and to what extent they interact with voters, journalists, and other politicians. Less attention has been devoted to the content of MPs’ tweets. We do not know much about whether politicians commonly use Twitter to post personal content, building an aura of spontaneity and informality, or the contrary, they tweet to communicate political positions on policy issues, and eventually respond to the preferences of their constituencies. Understanding how legislators use social media platforms is critical to assess their representative function and, therefore the quality of democracy. To better understand legislators' attention allocation strategies, we compare MPs’ Twitter activities in Italy and Spain from 2013 to 2022; the two cases provide rich variation between party systems and electoral contexts. We consider the role of gender, seniority, party affiliation, committee membership, and the electoral cycle