The city government and the teachers union are officially in a truce, but that has not stopped a confrontation on the Internet, where the union president and the Department of Education’s no. 2 adviser are meeting this week on a national education Web log.

Christopher Cerf, a top deputy to Chancellor Joel Klein, was a “guestblogger” last week and the United Federation of Teachers president, Randi Weingarten, is posting this week at Eduwonk.com, the Web site of the co-director of a Washington, D.C., think tank, Andrew Rotherham.

In a post, Mr. Rotherham said he picked the New York City leaders because “these are also two important players nationally and the issues are representative.”

Mr. Cerf’s first four columns addressed teachers, principals, and teachers’ pay, but he did not mention Ms. Weingarten by name. A running thread was that public schools will improve only when public schools get better teachers; to do that, he said, it would help if teachers could be paid according to their students’ test scores.

In her posts so far, Ms. Weingarten has explained how test scores should and should not be used, denouncing “the inappropriate linking of the results to important decisions about a student’s or school’s future.” She has not addressed Mr. Cerf by name, either. In an interview yesterday, Ms. Weingarten said she planned to write about data and test scores before Mr. Cerf mentioned it in his posts, describing the overlap in subject matter as “serendipitous.”

Blogs about schools have proliferated along with blogs about every other subject. Joseph Williams, the executive director of a New York City-based political action committee, Democrats for Education Reform, writes an education blog. He said the art is to be lively and avoid dragging on. “It’s harder to do than many people may think,” he said.

Both Ms. Weingarten’s and Mr. Cerf’s posts are many paragraphs long. They have other similarities, including a shared call for working together. “It is time to think differently and act boldly. The union is ready; will others be as well?” Ms. Weingarten ends her first column.

She elaborated in an interview yesterday: “I find that this notion — of management gets up and says, ‘Let’s blame the teachers and the teacher unions,’ and then teachers get up and say, ‘Don’t blame us, you guys are terrible rotten people.’ I think that adversarial-ness, while important on some issues, disserves children over the long term.”

Mr. Cerf’s fifth column, about politics, also calls for cooperation, arguing that the UFT and DOE’s agreement on the importance of good teachers should be “fertile terrain for important work.” “Shame on us,” he writes, “if we can’t find a way to tackle it together.”

In an interview yesterday afternoon, Mr. Cerf said he had not yet read Ms. Weingarten’s column, which was published Monday.