Cloud computing is the idea that you can store information and process information on another computer using an online contection. This is done for convenience sake but it has many issues associated with this structure. Firstly the name 'Cloud computing' is misleading, it is designed to hide the fact that these tasks are handled run on a computer that is controlled by someone else other than the direct user. When ever you see the term 'cloud' in relating to computers, think 'someone elses computer'.
Examples of this are Google Docs, Microsoft OneDrive and Amazon music. These are just a few of many thousands of similar products but all of them have the same problems. The big issue is that when these tasks are provided by someone else, they are the ones in control - not the users.
When you store any private data in an online service, there is no guarantee that your information and data is secure against others from looking at it. As mush as the people providing this (dis)service can talk about security, there is no way for you to personally verify these systems. This is a major breach of privacy as it means that your personal information can be collected and cataloged without your permission. A side issue is that systems like these are required in a school or work settings, this should never be a thing. To force people to give up their privacy in order to get an education or work is immoral.
A lot of these products are called 'Software as a Service' or SaaS for short. This is where a program is loaded into your web browser so that you can use a program that is only provided by the people owning the server. While these are not inherently non-free software, the vast majority of them are proprietary. This is similar to the issues of Java script (LINK HERE) in that just because the program is more transparent to the user doesn't mean that it is not mistreating you. If you cannot study, share, modify and share the modified code then you are not running free software and am being mistreated. These programs can emulation a wide variety of programs that you would typically use on your computer outside of a browser. These can be document editors, graphics editors, music players and similar functions. All those functions can be performed locally using your computer hardware and do not require an external server to provide the program and data everytime you need it. With SaaS, if the serve goes away so does the program and data. Because the program is loaded from the server every time you need it and the licenses typically do not allow you to use them as you wish. Unless you can get the four freedoms, you do not have free software and are being mistreated.
These same issue also persist in steaming media. Almost always these sites use DRM to prevent people from making copies of the content that are being distributing. While this is done to protect copyright for the content holders it is done by using non-free software. In trying to hold on to their rights they force you to drop yours. While the whole issue of creative works copyrights is outside of the realm of software - we believe that using a free content license such as Creative Commons is a good way to treat people in regards to your works - if the creator does not want to do this then that is their choice and should be respected. But it is another issue to choose a non-free license for a works and then force people to use non-free software and all its issues just to enforce it. It is better for the artist to not make it available digitally than to entrap people just to use the distribution platform of the internet.
Streaming media has the same control issues as Saas. The content providers will not only have the ability to track your consumption habits but they are also are free to take away this media when they wish or are forced to by the content holders. This has happened many times over the years, from music to books and movies. Even if the software running these platforms was made and distributed with free software; the content still has to come from an external source there is the risk that you will lose access to these works when the people running the server either lose the rights to the content or decide not to run the server any more.
You are best to avoid using these services as they do not respect your freedoms and actively work against you and your data.