A warning: when you contact me make sure it's not unsolicited, automated, template, mass-sent drivel. If you do, it'll end up on the Spammers List. (And I might just get someone evil to curse you.)
A direct message on Twitter is probably a good start if you need a quick answer to a simple question.
The Tackorama Steam pages is also a good place to leave a comment or ask a question, especially if it's about a game.
Comments are currently disabled on the YouTube videos (blame trolls). However there are ways to contact Tackorama via YouTube. But I wouldn't recommended it.
No Facebook page. I really don't like their idea of privacy and think Zuckerberg et al need to fuck off.
Tackorama is based in London, UK. It is a registered limited company (no 09259894) and the registered address is:
71–75 Shelton Street
But I wouldn't use snail mail if I was you because that address is for official business (and has to be displayed, says UK law, even though it's not Tackorama's actual location).