Just setup this tool today for our clients, it does a lot of daily checks for things that go wrong and can have a huge impact on your business! Obviously several items are key for SEO so it's great for that but just doing domain monitoring alone is great
It's amazing how many times I, and people I know, have had near misses (or downright dropped balls) with renewal dates for SSL certs and domains. Looks a really nice way to keep track of the "boring" stuff like that.
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I love this. On day 1 it picked up the fact that a key non www to www redirect had dropped off for a client. Just the simple checks that easily get forgotten and are a bit of a chore to manually carry out. It's like a really good SEO assistant. Except it costs less than a person. And never calls in sick. And it doesn't forget something that a client then finds and consequently leaves you feeling dumb.
I love it.
tl;dr Marketing