Hi Michael @zenman,
We'll be happy to shed more light on the situation of songs suddenly becoming unavailable.
First up - you're right, it's not an issue of server space. We use decentralized cloud networking services in order to ensure both near-unlimited storage capacity as well as dynamically rerouting users to their closest available server to ensure smooth, buffer-free connections.
Our desire is to have as much content on Spotify as possible and do our best to add hundreds of new tracks each day. But we don't actually own any of this music. Every single track has its own rights holders and we can't make anyone decide to license or upload a track to our service. If a track goes missing, this is not because we don't want it on our platform, but because something must've changed with the rights agreements. You can find our official statement on the matter on our website as well.
Talking specifically about "Gate of Dreams", it seems its still available and we managed to find it over here:
Is this what you are looking for? If it got removed previously, it means the licences needed to be renewed, which luckily it seems they have been.
There's also no differences in content available between desktop and mobile apps. We want people to be able to enjoy their music no matter the preferred device, their age, country or any other demographic factors. This is one of the main reasons why we develop Spotify for a variety of devices and why just in the past few months we've launched in 77 additional regions. And we most certainly don't want to make a long-term fan unhappy.
We can definitely be contacted directly. This can happen here on our Community (we hope this post is evidence of this), via email, chat, twitter and Facebook - we've tried to provide different options and have listed those on our website here. So if you rather choose one of those methods to get in touch, rest assured that someone will reply.
While we do not control what content is on our platform, we still try our best to add as much as possible, without focusing on specific genres, charts or demographics.
We hope we were able to help you understand how content availability works and that it is really no desire for us to have less of it in any way. We'll continue with our efforts to provide you with all of the world's music under one roof. And even if we aren't able to achieve this, admittedly lofty goal, we won't stop trying.
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