While some people in Bulgaria joined the protests against both governments, and while there were small amounts of protesters who were out on the streets throughout the spring of 2013 and effectively "linked" the two series of protests, the reasons that sparked off the two waves were different.
The winter protests began due to high electricity prices and morphed into anti-GERB protests, while the summer anti-BSP/MRF protests were sparked by the election of media magnate Delyan Peevski to head the national security service.
Many of the people who participated in both waves of protests are unhappy with the oligarchic model of governance that they claim has taken hold in Bulgaria, which leads to monopolies or near-monopolies in many spheres, such as energy (central to the winter protests), banking and media (central to the summer protests). These, in turn, are perceived as having a strong influence on the nation's political scene. LINK Protest Bulgaria