But you know who has already built Mixpanel? Mixpanel. And they’ll let your business use if for a couple hundred dollars a month. Starting today, not six months from now when your version would be finished.
Better still, if you use Mixpanel’s Mixpanel instead of the one you built yourself, you can have your dev team develop your product during all that time they would have otherwise been building somebody else’s product for internal use.
Build versus buy. It’s a thing for a reason.
The raw data is with you. You don't need to wait for 6 months but launch a version with limited features and can continue developing it slowly, until it achieves whatever feature parity you are aiming for.
I'm starting to think that most of these analytics services are more trouble than their worth if you have a good engineering team. A few metrics API's + timescale DB + Grafana goes a long way. If you have a differentiated business you're probably measuring something unique. And if you're measuring something unique then you're better off building your own analytics.
Also, realistically most businesses are built on top of databases. So the most important stuff is in the databases anyway. So might as well just put metrics in SQL too.
But I agree that applications have unique things about them and for those, people need to implement their own metrics to measure whatever interests them. In that case, the current best choices for time-series database are InfluxDB and Prometheus. They provide very simple APIs and tools for collecting and transmitting metrics, and if you prefer to store aggregations of your metrics instead of the many individual data points, you can use the very simple but powerful StatsD api/client/library/package.
Shameless plug: My company HostedMetrics (https://HostedMetrics.com) offers hosted and fully managed InfluxDB and Prometheus. It includes everything needed for a turnkey metrics platform that is ready to accept your metrics the moment you create an account: StatsD for data transmission, Grafana for dashboards, and the alerting functionalities of InfluxDB/Prometheus.
But for every other biz that happens to be on the internet, ie e-commerce, not having to rely on a tech team for implementing various services has some value. If you consider that some websites can only be updated every few months or so, having a third party manage that for you is a life-saver.
I've seen / helped too many marketing folks try to get some services (read pixels) implemented and it's always been a Shih-tzuh :)