Twitter's magic sauce is based on 140 chars, recently also supporting 240 characters although it's the less popular format and statistically less-read compared to 140 char. But i guess with Steem's incentivisation, 240 would be more detailed and contain more information to work better as a comms tool. The joke is that Deep Thought dreamed up the number 42 and if we reflect on it as base-10 creatures, we end up decrypting the message from 42 to 240 lol