The stand-up meeting is there to let the entire team (not just the ScrumMaster) understand the state of the team, and allow for immediate course corrections. Scrum works best when the team, and the ScrumMaster, use the information from the daily stand-up feedback to reallocate tasks, adjust expectations, and coordinate with other teams and stake holders.
It is not uncommon that, when a member of a team is blocked or delayed on a task, another team member offers a solution or to help with said task.
It's important to remember that the stand-up meeting not a status meeting. That said, the ScrumMaster, just like any other member of the team, should leave the meeting with an understanding of the state of the project.
Three Questions
#1 What did you work on yesterday? asking this helps understand which tasks are done.
#2 What will you work on today? this is the form for a team member to pick up a new task.
#3 What are you blocked on? this is how dependencies and blocking issues are identified.
From a project management stance, part of #3 (or a separate issue) is 'do you think that we are still on track to hit the Sprint Goals'? - while not part of the classic three stand-up questions, it is helpful as a source of team state information.
Duration and Recurrance
The daily standup meeting is supposed to be a light-weight, brief meeting.
A rule of thumb for scheduling is 'one minute per participant' or 'fifteen minutes overall'. Do not hesitate to interrupt longer discussions and push them to a 'post standup' meeting.
Classic Scrum has the daily meeting happen, well, daily. Other practitioners have had good results with 2-3 stand-up meetings daily, on fixed days
