Personally I think this is a great, inexpensive idea. It's one of those guerrilla marketing type tactics that rather than directly stating the message attempts to invoke people to ask the 'what is that' questions or perform the search.
Not too long ago there was a billboard in town with just the phrase Use Your Noodle.com or something like that. Not saying what the product/service was in anyway, just 'daring' people to look it up or goto the site itself to find out.
In the case of Steemit, I'm a rather big fan of new non-crypto, non-tech people 'learning backwards.' For example, I tend to wait to explain the Steem -> Btc -> fiat process until they have $ in their accounts and want to actually do their first withdrawl. (Which I personally think is important for new users to do at least once, even if for a smaller amount, to know it's 'real.') This gave me more time before their 'eyes glazed' over since they were more motivated to understand things that were a bit more new/complex compared to what they were used to.