The vast majority of my interaction with other people online is via email or IRC. Generally speaking, emails to me will get through to me quickly and I will usually respond within a day.
You can contact me via my public key, or by emailing [my-forename]@[my-surname].net.
You can also try private messaging on other websites that I use, but it may take me longer to notice those.
You can contact me by telephone or post, but please email me for the details. I am normally located in London, UK.