Talk about ending the year on a high. Music streaming leader Spotify posted its first ever quarterly operating profit and closed out 2018 with 96 million paid subscribers. Aptly, the Swedish firm toasted the achievements with a duo of acquisitions, and also handed an unexpected commendation to a certain hardware partner. The thing we like so much about Spotify as a business, is that generally with services offering both a free tier with advertisements and a paid tier without ads, the balance of users naturally weighs heavily towards the free tier (more so in Europe and elsewhere than the US). Yet such an imbalance in swing is not the case with Spotify. The premium service has closed the gap on…