In fact, it was very easy to find out what it was about - I think I even saw someone post that news a few days ago. In short, here's what it's all about :
Coinfloor, the U.K.’s longest-running exchange, launched a mix of large digital billboards and posters across London’s main tube stations. Meanwhile, Luno, the crypto exchange recently acquired by Digital Currency Group (also the owner of CoinDesk), combines its London Underground ads with 650 Greater London buses and a bunch of large roadside billboards.
Not only have big investors realized it’s time to invest in Bitcoin, everyone in the crypto sector seems to have decided it’s the right time to promote - and public transportation in such big cities is definitely a good choice for advertising.