You can comment anywhere on HIVE, (threads included, but not long-form posts,) with the words !remindme followed by a time, minute(s)/hour(s)/day(s) etc... My app will parse it, put you in a list, and remind you when the time comes!
Example: !RemindMe in 1 Hour
Couldn't parse the time for your reminder. Please use a valid format like 'in 2 hours'.