And there's also a growing number of analysis tools and services that could provide particular data which saves time and effort. I think the most used right now is walletexplorer.com which does address grouping.
May be this is what am really looking to understand, after know that it's not possible to link addresses, so what's it's all about those analysis tools and what help for?
Ofcourse it is. Every bitcoin is coming from somewhere.
Unless you use some sort of mixer, there is a really big chance certain tools, (especially from
FVEY Five Eyes) can trace your Bitcoin from where you currently stored it, to where you first bought it, which date, which exchange, which payment method you used.
*Almost* every exchange nowadays requires KYC, and has your banking info. it's really a myth that bitcoin offers any privacy at all when used against the government without proper measures as i described above.
As i said, a mixer breaks this chain. But yeah, if the mixer is controlled by the group described above, it's not of much help. (Which could be the case for any mixer really, we simply don't know who's behind them.)
Which is quite freaking dangerous when you think about it. I have no idea if Chipmixer isn't controlled by the CIA, serving as a huge honeypot.
Anyway.