By setting Screen Updating to False at the Start of the macro, you will not only stop the constant screen flickering associated with recorded macro, but also greatly speed up the execution of the macro.
If you write a 0 (zero) all hidden rows will be visible again, and old values in column A are deleted.
In the last example you can type something in cell A1, and all rows (except row 1) that have the same value in column A will be hidden.
While Excel will set this back to True whenever focus is passed back to Excel (your macro finishes) in most cases, it pays to play it safe and include the code at the end.
You may even find in some cases that Screen Updating is set back to true before your recorded macro completes.
You will find lots of tips and tutorials for using visual basic in Excel.