It really took off from there. Clinton said she and Sanders "share the goal of trying to make college affordable for all young Americans," while Sanders decided to "concur" with Clinton about women's rights issues. Clinton "completely" agreed with Sanders on police reform. And then, doing his best Yoda impression, Sanders responded to Clinton's position on prison reform by saying, "Nothing that Secretary Clinton said do I disagree with."
The second half of the debate finally featured a few disagreements — which were broadcast as such, often using the word "disagree" — notably on trade agreements, deportation policy and the question of how critical Sanders has been of President Obama. Yet they were still "in vigorous agreement" on Social Security funding. Vigorous.
By the end of the debate, the two of them combined to say some form of "agree" or "disagree" more than 50 times.
Their long string of agreements wasn't entirely unexpected. Sanders's candidacy has forced Clinton to spend more time discussing certain issues – especially wealth inequality and the wage gap – than she might have otherwise. But even with those issues brought to the fore, a lot of their positions are similar, even if their proposed solutions are different. Their list of agreements might be so long, in part, because Sanders tends to speak in broad generalities and focus on perceived injustices, while Clinton has a habit of using very specific stories and policy proposals to burnish her credentials.
Clinton also has incentive to emphasize her agreement with Sanders on many issues. It assures the base that he's not more in-tune with their issue positions than she is, which allows her to then make the case that she can actually get things done.
After six Democratic debates, both candidates have certainly had time to discuss their positions. The challenge left to the moderators of remaining debates is finding more areas where the candidates disagree than where they agree.