At 6:44 p.m. on July 15, Democratic Party of Japan lawmaker Seiji Osaka posed a question on his Twitter profile: "I think bringing the voting age down to 18 years old is OK. What do you think about it?"

Within 10 days, 198 users posted their opinions, and one even summarized the debate — 76.8 percent who expressed views supported lowering the voting age and 23.2 percent were against it.

Twitter — a micro-blogging service where users share short posts and connect with readers, or "followers," through their profiles — is rapidly gaining popularity among politicians ahead of the Aug. 30 Lower House election.