"the amount of time people spent on the Reddit website by close to 16% between June 12 and 13" - what does that mean?
In the article, the full sentence is,
That "blackout" movement, which briefly caused Reddit to go down, dropped daily traffic by about 7% and the amount of time people spent on the Reddit website by close to 16% between June 12 and 13, according to the data shared by web traffic analysis firm Similarweb.
So basically the amount of time people spent on reddit dropped 16% between June 12 and June 13.
"Web traffic of the platform also declined to about 52 million" - 52 million ?
Yeah that could be worded better. No units. Resumably it's about the number of visits.
Again, the full sentence is,
Web traffic of the platform also declined to about 52 million on June 13, compared with averaging nearly 56 million in the days prior.
So a 4 million drop in number of visits.