1. There should be a check on a customer before they can post in the forum and if they are a new customer and / or only have low Karma then when they click the "New Topic" button it should display the message
Dear XXXX,
Thank you for registering with nopCommerce. We see you are wanting to immediately post in the forum. We can appreciate that new users are often in a hurry to seek help and get their website up and working.
Did you know that many questions and responses have been posted in the forum over the many years since the nopCommerce website was originally developed. This means that you can search the forum and there is a good chance you will find a solution to your issue or question. Click here to search the forum
The nopCommerce system also has extensive documentation available at this link
In addition nopCommerce offers a number of Premium Support options See
https://www.nopcommerce.com/en/nopcommerce-premium-support-services
We encourage you to consider using one of these options to help you find a solution. If you still have problems you may return later and post a new topic in the forum. Then we are sure one of the many community members from around the world will then be able to help you find a solution.
Thank you
nopCommerce Team
2. After a set number of hours (maybe 4 hours) they can post a New Topic but while they have low Karma they can only create one new topic per day.
3. The forum test should check the heading entered and not let the customer create a new post with differently similar variations of a recent previous post
4. While a customer has low karma the forum post should allow a customer to propose a New Topic then search and check for all posts about the same / similar topic proposed and make a list of suggested existing posts (this is a bit harder but it can be like and AI learning system that develops over time)
If answers still not found then say "Still not find an answer - Click here to post ?" then allow them to fill in the body of a New Topic post
There are probably a few other rules that can be applied but these could be a good start :)
Thank you