Vevo has had a rocky year, with a yo-yo experience of being up for sale and then taken off the chopping block. The launch of YouTube Music Key is also a potential risk for Vevo’s business. The new paid subscription service offers ad-free viewing of music videos and other artists’ content, which is Vevo’s bread and butter. Vevo has a big presence in the free version of Music Key, available now as part of classic YouTube. The subscription portion of Music Key launches tomorrow. Time will tell whether Music Key will influence Vevo’s traffic and business prospects.