Can you briefly say for overall development what information can be obtained using Cloudflare?
Everything:
The security implications are that Cloudflare can read everything you send to or receive from the server, including your cleartext password and any PMs you send or look at.
What I meant is that Cloudflare can see your unencrypted password when you log in. It's still encrypted from the real server to Cloudflare and from Cloudflare to you. So it's not blatantly insecure except in that Cloudflare is very probably an NSA honeypot
Ok. Has this topic already been discussed on the forum, where I can fill the gap in my knowledge?
I've seen some discussions about it. A good place to start might be different ANN threads on the
Service Announcements board.
the bitcoin network was considered anonymous
It never was. Bitcoin is pseudo-anonymous at best.
everything is going to the fact that not a single transaction will be carried out without mixing services.
That's not needed. It really depends: you probably wouldn't mind paying for your coffee from an address linked to the address you use to pay for your lunch. But it's not wise to let your local barista know you own $100M in Bitcoin, and you may not want to pay for sexual services from the address you received your Christmas bonus on.