Five channels with ten thousand subscribers each are not fifty thousand people. In a narrow field the same readers subscribe to everything, and real reach can be a fraction of the sum.
Where it comes from
Someone interested in a subject follows several channels about it — normal behaviour. The narrower the field, the stronger the effect: in a niche with a dozen notable channels, the core audience reads nearly all of them.
How to see it
- From the second placement. The first paid post in a niche brings a noticeable wave, the second in a neighbouring channel brings half at the same reach. That is overlap, not "creative fatigue".
- From chat membership. Collect the members of two groups in the same field and compare the lists; the share of matches is directly visible — cleaning a database.
- From commenters. The same names under posts in different channels is the quickest informal check.
What to do about it
Do not add reach together. Planning a series of placements in one niche, assume diminishing returns rather than a sum — buying ads.
Spread into adjacent subjects. Overlap is weaker there and the growth is honest; conversion is lower, which is the trade.
Use repetition deliberately. Seeing you a third time is often what converts. That is not wasted money if you know you are paying for frequency.
Where overlap helps
For commenting it is good news: it means being present in a few key places is enough, rather than a hundred — how many channels you need.
And for research: strong overlap identifies who genuinely shares your audience rather than merely writing on a similar subject — analysing competitors.
How Neurogram does this
Everything above is manual work that runs into the number of hours in a day. Neurogram does it on your own accounts and without you: it collects channels and audiences, writes comments and replies with a language model, and keeps limits and quiet hours so the accounts survive. See pricing or look at your case.