The best way to contact me is via e-mail: I usually answer within 1 day. If that doesn’t happen, feel free to ping me via instant messaging (on Google Hangouts, Skype or Facebook Messenger), Slack or IRC (mainly on Freenode), where I go by “phretor”.
If you need to communicate with my privately, use my GPG public key. Its fingerprint is C42B 0CC7 6191 5B69 2C68 E88F 9693 4CDE C0BB EBCF. If you prefer modern alternatives, yes, I use Signal (and you should, too), and Twitter.