During Congress the best choice to contact us is to call 1780 on DECT.
If you want to participate, you have to attend an angelmeeting first. The meetings for 35c3 can be found at https://events.ccc.de/congress/2018/wiki/index.php/Session:Subtitles_Angelmeeting
Please use or IRC channel for small questions, especially if they aren't of relevance for the whole Mailinglist.
Hackint has a WebIRC interface available which you can use if you don't normally use IRC.
Our channel is '#subtitles'. Please enter your nick. Any 'WebIRC1234'-style nicks are very annoying to regular IRC users.
Also note that many people host their client on servers, so whilst they are online in the channel, they might not be getting your messages straight away. Just be patient, they're usually 'on-keyboard' multiple times a day.
Again, please don't post simple (eg. 'How do I', 'How should I', 'Mind if I') questions to the Mailinglist. That's what the IRC channel is for.