Docket Monitor has a long and sad history. It was a pretty slick piece of technology. It took cases on the federal courts as well as lots of state courts, and kept checking the docket on a schedule to see if there were any updates to your cases. If it found an update, it would send you an email or an sms with a message saying what had been updated.
Turns out the biggest problem with this is that the main lawyers on a case already receive notifications. So this would only be cases that you weren't directly listed on. Think for paralegals or junior lawyers on a case.
We had a marketing strategy, pushed some volume through a cpc campaign, and ended up with nothing for signups.