This method of promotion works great in the so-called “thematic” circles of communication. Users recommend the channel about stbemu codes along the chain and that, as a rule, quickly acquires new readers.
True, for the effect of word of mouth to work, you need to publish really useful and interesting information in the Telegram channel. Really cool content sells like hot cakes, in such cases you don’t have to spend money on channel promotion at all.
If the owner of the channel is a media personality or just a famous person, word of mouth in this case will work even better than any paid advertising.