You could probably have a function check your website at most once a week by calling your update function when starting some specific GUI/GUIs and storing a timestamp with setpref.
I don't know about 'usually', but if you want to see a suggestion for an implementation, you can check how I did it for my PhotoAnnotation FEX submission. I suspect if would be much better to have a website under your own control, although that will break in the future when you discontinue your website. My method will break once Mathworks decides to change the URL structure. It is your call which of the two you expect to happen sooner.
