Is this mail from you?
Mails I sent are signed with my GPG key (fingerprint mentioned above) – which can be verified with GNU Privacy Guard, which is also the cause for the "signature.asc" attachment on my mails. If a mail claiming to be from me is NOT signed be VERY careful – it is very likely SOMEONE ELSE trying to trick you into opening an infected attachment or visit forged websites. Additionally, for the benefit of people and mailservers who do not know about GPG signing, my mails should pass SPF, DKIM and DMARC as well even if I would encourage you to prefer GPG if at all possible.
If all these words make no sense to you fear not: Mails from me usually don't have an attachment (other than "signature.asc" which all should have). Especially no executables (".exe") or Word documents (".doc", ".docx"). My mails are text-only (no HTML mails!) and in the event I have to sent documents with images and co around they will be in Portable Document Format (".pdf"). If you are in doubt if a mail is really from me, feel free to contact me!
Social networks, cloud- and other services
I don't own nor use any Accounts on so-called social networks and similar services and I don't intend to change this, so please avoid sending me inventations for those. In other words: I don't have and I don't want to have Accounts on Facebook, Twitter, LinkedIn, Instagram, Flickr, …. On some of these services might even exist accounts with my name or nick – but that is NOT me.
If you want to contact me, it is best to do it by mail. Even on sites I really have an account on, I am hardly reading/responding in a timely fashion, if at all…
abuse of contact data
I have no illusions: Publishing a mail address seems to be interpreted as an implicit invitation to send Spam, but for the record: No, I don't want advertisements, win- and inheritance notifications or medical enhancement special offers from you. It might come as a surprise then that I even post my postal address and a phone number… how dumb can you possible be, right?
The thing is: My Address is already public, e.g. on record by the .de-Domainadministration DENiC. Further more I am legally required to publish such information so I can be contacted (vgl. Impressumspflicht) as only private websites are exempt from this and a bit unclear what private is exactly in this context…
It should be obviously, but just like with the electronic mail, my postal mail address isn't written here to attract advertisements. Quite the opposite. And if you happen to have the "wonderful" idea of dropping by in person at my doorstep: Don't. Just don't. It will not turn out well for you…
Same thing with the phone number. I don't like phones anyhow, so you would be fighting an uphill battle against a very displeased me… Save yourself the time and effort and annoy someone else instead (or preferably nobody).
And just so that nobody can say I haven't warned him: The law is on my side – and I will not refrain from using it if you abuse my data.