Our portal accounts now measure uploads by file size –not the size on the Sia network, as we did previously. We have also introduced limits to each tier for the number of uploads allowed.
It's important to know that accounts limit uploads with two distinct metrics: storage amount and number of files.
The reason file count is limited is because of how files are stored on the Sia network and how much redundancy your data has. For more info on how Skynet uses Sia, see Skynet Basics and Tier Comparison.
When using Skynet applications, they will often save data to Skynet in the background. This usually takes the form of formatted text (called JSON) and it might be a post you made, your friend list, or your user profile. The files are important data for the Skynet apps and will be attached to your portal account so that they remained pinned and available on Skynet.
Download usage is much more straightforward than uploads. The files you access are listed as downloads.
When using Skynet applications, they may load data in the background. Just like on the traditional web, this happens very often while browsing a website. Some of the loaded material may never even show up in your web browser.