Facebook Reach.

I have recently posted my affiliate link on a Facebook Group with a total membership of around 200k, accompanied by a short blurb outlining Wealthy Affiliates' value and free training, etc, for starter members. This got me to thinking, "I wonder how many of the 200k will actually see my post? So I enlisted the help of Gemini AI and asked it the question. Its response went as follows.
That's a great question, but the number of members who see your post on a Facebook group with 200,000 members is likely to be very small and is affected by many factors.

A realistic estimate, based on typical Facebook group engagement rates, would be somewhere between 1% to 5% of the total members, meaning 2,000 to 10,000 members might see your post in their feed, and a much smaller percentage will actually read it.

The exact number depends primarily on two factors:

1. Facebook's Algorithm (Reach)

Facebook's algorithm determines who sees what in their news feed. In a large group, your post competes with thousands of others, and the platform prioritizes content that is already generating engagement.

FactorEffect on Your Post's ReachEngagement RateThe faster your post receives likes, comments, and shares, the more the algorithm will show it to other members. If it gets little immediate engagement, its reach will quickly flatline.Member ActivityFacebook only shows the post to members who are active in that group or are frequently engaging with similar content. Inactive members (which is common in large groups) won't see it.Post TimingPosting when the group's members are most active can give you a vital initial boost of engagement.Export to Sheets

2. Group Dynamics (Visibility)

The nature and management of the group itself play a huge role:

• Group Rules: Many large groups have strict rules about promotional content or affiliate links. If your post is deleted or marked as spam by moderators, your reach is instantly zero.
• Post Format: A simple text thread is less likely to stand out than a post with an engaging image, a relevant GIF, or a video.
• Topic Relevance: If your thread is highly relevant to a hot topic that group members are genuinely interested in, the initial click-through and comment rates will be higher, leading to increased visibility.

In short: Don't focus on the 200,000 member count. Focus on creating a post that provides value, asks a question, or shares something compelling that will motivate the first 50 people who see it to interact, thus signaling to Facebook that it's worth showing to thousands more.