Yeah, this "btw I have a newsletter here" seems overly promotional. HN as a forum doesn't have support for "signatures", then it feels a bit off to end every post with something not really relevant.
The grey area is people constantly linking to their own blog, but the linked post is relevant (example [0]). Like, it's good when people post relevant links to diver deeper, but when it's constantly your own content, that irks me a bit.
[0]: https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...