Signups were slower than I'd hoped although people did seem to be using the site once they signed-up so that was promising.
I decided that there needed to be more features, for both Free and Pro users and I spent the next few months developing more advanced features:
Rate limiting of SMS alerts :
Free plan upgraded to 60 monitors:
Custom alert schedules (i.e. only get alerted if your site stays down for x minutes):
Bulk manage monitors (bulk import, edit and delete):