Chains topics on Habré

The idea is as follows:
Watching Habrom for several days in a row, I noticed that the community affected by some good and interesting topic (for example, coworking or the topic of pricing in web design) begins to write topics in a similar narrow topic, describing them (topics) as an answer (or even a parody) to the previous ones.
So, I think it would be nice to be able to link such topics together. That is, I enter the topic, and I see below a block with links to similar topics (there is a similar feature on Lenta.ru).
This functionality can be implemented as follows (down):
1. Automatically by tags (for example, if 80% of tags to the topics match)
2. Manually by the author (I don’t even know how to do it better, but it would be ideologically correct)
3. Manually by user

Anticipating the indignation of users that similar topics are combined in blogs I want to say:
1. Not always I need to look at all the topics in the blog. There are blogs with a huge number of topics, and a couple of pieces can be included in the selection list.
2. The topic is not always included in the blog. Moreover, I may need to include in the selection of a sticky topic.

This topic is more suitable for blog Ideas for the site.
UPD: Moved to blog Habrahabr - Ideas for the site