Thanks, @tabris! I'm now set up.

I hadn't used Telegram before, so it took me a bit of tinkering to discover how to set it up. Simply clicking on the link you provided (https://t.me/SteemAlertBot) gave me an error in Safari. Once I downloaded Telegram on my iPhone and established an account on Telegram, I was able to discover the bot by entering SteemAlertBot in the Telegram Contacts search field on my iPhone. After that, it was quite painless setting up the notifications via the /user (my steemit username) command. For anyone else experiencing similar problems, I suggest you either use the Telegram phone app or use the link provided on Chrome (which is a supported Telegram browser, Safari isn't). Thanks, again for providing this free tool!