If you set up a dashboard or a dedicated news page, that you want others to use, you can offer them a Personal News Feed on that page, too. Simply insert the macro at the desired spot. Whenever someone visits the dashboard or news page, he or she will see his or her own Personal News Feed. That allows for a highly customizable news concept.
Users can select the spaces they want to read news from themselves from the frontend, without editing the page or macro. Of course they'll only be offered the spaces they have permission to read.
If your Confluence contains a lot of spaces however, and even more so if only some of them publish news at all, you might want to configure the Personal News Feed macro. You can set it to only offer those spaces for subscription that have one or several space categories applied. Simply type in the name of the relevant space category or categories. For example if all the spaces, that publish news at all, are labelled "news" as space category, you'd type in news. Now when users want to pick their selection of spaces for the Personal News Feed, they'll be offered only those.
You can subscribe to different news sources for your Personal News Feed. This is not done from the macro configuration but from the page your macro sits in. You'll find a button "Button name" at the bottom of your feed. Click it to select the spaces you want to read news from. It will only show you those spaces you are eligible to read.