re·cip·ro·cate
rəˈsiprəˌkāt/
verb
respond to (a gesture or action) by making a corresponding one.
"the favor was reciprocated"
synonyms: do the same (in return), respond in kind, return the favor
"I was happy to reciprocate"
I'm not suggesting just blindly voting for everyone that votes for you. Just that if someone takes the time, maybe you return the favor and check out their stuff.