Things haven't changed that much. While students do blurt out questions, that is frowned upon. In general, when teachers are presenting material, they expect that students will raise their hands and wait to be called on. From experience I can say that this is preferable for several reasons.
1. The question may be answered soon, without any interruption necessary.
2. The question may not be relevant and can certainly wait.
3. When people randomly shout out questions, the speaker can lose her train of thought.
4. When students start randomly shouting out questions, there can be several students asking at once. This makes it very difficult to follow which answer applies to which question.
Do some students ask questions without raising their hands? Yes. It is discouraged and frowned upon, though.
Some teachers have other ways for students to indicate that they want to ask a question, for example, by standing a book up on their desk, turning a card over (red indicates the student has a question), writing their name on the board, and so on. These work well when students are working at their desks, with partners or in groups, and the teacher is moving around the room.
*waving at hm*