Does flavored yogurt qualify as "dessert" or is it considered part of the meal?
If it's dessert, would it require its own blessing?
What about plain yogurt?
This question might be a dupe of what @AvrohomYitzhak linked to. Either way, read this to get a general sense of what's considered "desert". Excerpt:
If one is already full, and he is only eating the deserts because he enjoys its taste, he would have to make a new bracha on the item.
Ice cream, sherbet, and candy all receive a separate bracha rishona. However, many Sephardim hold that one should not make a Bracha on ice cream in a meal.
So, if you are talking about plain "soft" yogurt (like Yoplait, Dannon, etc.) whether it's flavored or not, if you are eating it because of its taste after you have been full from the meal, you would need a bracha, based on above.
If by yogurt, you mean "frozen yogurt", this may be considered like ice cream (CYOR on this concept, as I couldn't guess on this one.) In that case, based on above reading, if you're Sephardi, you might be exempt.