The fastest way to reach me is email. I read everything, and I answer most things within a few days.
App support
If something is broken in one of the apps, email is the right route and the quickest. Please include which app, your iOS version, and what you were doing when it went wrong — it saves a round trip and usually lets me reproduce it the same day.
Corrections
If a guide has something factually wrong, tell me. Include the page and what is incorrect, and I will fix it and update the page date. I would rather be corrected than be wrong in public.
Press and partnerships
Same address. If you are writing about one of the apps and need screenshots, icons or detail, ask and I will send whatever is useful.