What is a visitor in a privacy-focused analytics tool? Can we have a returning visitor when it is not tied to identity over time and across visits? How can we even interpret these numbers?
Let's summarize the ladder of identity on the web: Logged in user > Persistent identity (e.g. cookie) > Ephemeral identity (e.g. 24h hash) > no identity.
Privacy-focused tools seem to provide the last ones while promoting the same advantage as the first ones! Coolness over effectiveness?
What's all the fuss really about?
It's worth noting that the question is not about all the different kinds of statistics these tools can provide without relying on a cookie but about the legitimacy and the relevance of the visitors' related statistics (e.g., new, returning, etc.).
Personally I have a background in metrics and reporting tools. I've been tasked to find and explain 0.3% differences between two reports or have cookie related (or timezone related) code getting reviewed by other engineers at previous companies. With millions of dollar at stake, Powerpoint meetings or investor or financial documention it makes sense to question every definition and the whole data pipeline.
> Coolness over effectiveness? What's all the fuss really about?
Ok, I admit, there's a bit of coolness factor. Paying $25/month to a small bootstrapped company (with a great podcast) beats feeding data to an ever growing global player (Google).
The privacy part, compared to other tools, comes from the fact that it's self-hosted, so no data is shared with 3rd parties, which is the best way to achieve data privacy. You can detect returning visitors in various way, an option in userTrack is to store the hash of IP + user-agent string of the visitor. It is not 100% accurate and if the visitor updates his browser or his IP changes it will be considered to be a new user. If the user is logged-in, you can tag each session with his username or user ID.
Also keep in mind that fully persistent identities rarely exist (unless the user is logged-in), as the cookies can be cleared at any point or simply be blocked/reset by the browser on each visit.
PS: I do agree that many privacy-focused tools are also not really private, because they still are a 3rd-party aggregating data across the web.