If 200 of them see the post twice, that means you've gotten 400 impressions, right? The number of times the post is shown, multiplied by the number of unique people who see it.
Now, if we're talking about reach, that means you only reached 200 people. That's the number of unique users who saw a post.
When we bring this to ads, it works similarly: as long as the ad is shown once to a user it will count as one (1) impression, which can be very misleading for Digital Marketing newbies, especially if it is displayed after a lead or when they leave the site.
However, the scope will only record those impacts where the uk phone number list user has the post in the foreground and the system "believes" that he has already observed it.
Twitter
On Twitter, the issue of reach vs. impressions is different than the rest.
The app is unable to measure the reach of tweets, as it is virtually impossible for the algorithm to tell whether a tweet was seen or just made an irrelevant impression.
For this reason, the network managers decided that impressions will only be measured when the tweet appears on the screen, as long as it is in the news section or the feed and in the search results.
That is, if you publish a tweet and it is seen by 200 users, 3 times on average each, it means it will have 600 impressions.