There are alternatives, if you really hate Twitter, or if you’d like to send me a longer message in a non-public space. If you’re someone I know, you could add me on Facebook; if you’re not, you can follow my profile and receive my public updates. More of a business query than a personal chat? LinkedIn is fine, though it’s terribly spammy; you’re more likely to get a fast response over email.
You could always be old-fashioned and send me an email, if you like. I respond to [email protected] as regularly as I can.
Finally, if you’re Tokyo-based, you could always just suggest a time to go for a drink.