How to correctly compose the semantic core of key queries?

Question

Search Engine Optimization

• How many impressions should I choose in Wordstat?
  
• How to choose requests?
  

After all, there can be many impressions, but not a single transition.
for example faced with a strange situation

• - the site is focused on equipment design - no traffic for relevant queries
  
• - for the irrelevant query "7 red lines" - both traffic (albeit funny) and a high position in the issuance.
  

Yes, many free links were posted on it, but on the main topic, no less, but even more.
And on "7 lines" - ONE page on the site, and on the main topic everything else.
I found out that when "7 red lines" are issued on request, sites appear that seem to have specially made this page, which is in no way connected with their main topic.
What conclusion can be drawn from this?

• Are there topics (humor, sex, death, etc. as in advertising) - which are catchy , give the activity of visitors?
  
• if the topic is below a certain threshold ( let's say 1,000 - 5,000 impressions) - such a request will not give any traffic even with TOP results
  

How then can you promote a forum on a technical topic that does not fit into anything "hot" ...

Answer 1

How many impressions should I choose in Wordstat?

In narrow topics, you need to take ALL requests
You drive in a word with stop words, take everything, then process it additionally if necessary, then all the other words in the same way - your whole core is ready
These are not banners, this is a search, if there is an impression, then someone will get the transitions
lots of reasons maybe need more details
you don’t need these topics, although there is a lot of traffic in them, the visitor will leave dissatisfied and you still won’t promote the site
Forums are promoted by teams creating the illusion of communication with each other at the first stage when there are no people. At the second stage, you yourself throw in topics for communication with optimized headings.
In general, you need a million small requests. What is a tech topic? For example, household appliances, let's take only one appliance - a washing machine: which powder is better, what to do, why it makes a lot of noise, why it rattles, why it jumps, hard water.
PS If you have a forum about excavators or atomic chromatographs, do not suffer nonsense - close it))