Yu, who established a reputation as a farmers' rights activist, opened the two microblogs on t.sina.com.cn and t.qq.com, two popular Twitter-like services.
He has recruited two volunteers and is planning to recruit more for the campaign that is scheduled to end in May.
Since the microblogs were set up on Jan. 25, more than 1,200 images of child beggars have been posted. The postings usually include the times and places where the children beg.
However, the number of followers has boomed during China's annual Spring Festival holiday week, a time of family gatherings across the country that started on Feb. 2.
In just two weeks, the microblogs have accumulated about 154,000 followers, including some local police authorities.
Growing numbers of ordinary people are taking photos or videos for publication on the microblogs in order to help parents locate missing or abducted children.
The postings came in dozens in the first couple of days, but now they came in hundreds.
"The public enthusiasm exceeded our expectations," said Hou Zhihui, a volunteer who maintains the microblogs.
The efforts are starting to yield some results, Hou told Xinhua. "Two parents have told us that they have seen kids in photos who are very much like their missing children, and they are investigating," he said. [ Some parents have reportedly quit their jobs and spent years traversing the country in search of their missing children.
The stolen children are often sold to childless couples or those who favor boys over girls. The abductors often force other children to beg. To earn sympathy, some have been deliberately handicapped.