When you receive GCMS notes you may see the upcoming stages of your immigration or visa file processing.
It could be anything from the coming medical forms to the interview arrangements. For example, an officer decides to call an applicant for an interview to clarify discrepancies in reference letters. You would be able to see in GCMS file that the interview is coming and be able to prepare well in advance, e.g. arrange needed documents, letters from employers.
You will be able to read in your GCMS file when your immigration or visa file will be taken for further processing, what are the next stages and may estimate how long it might take CIC to finalize your case.
If you need help understanding what is written in your files and what to do next, you could always come to us for assistance. We would also be glad to help you getting copies of documents you submitted with your file, just in case you have lost them or simply need another copy.