This was somewhat intentional. I had a larger plug at the beginning initially. I decided it did not seem genuine enough, and would take away from the content.
You are clearly genuine, but also a little naive business wise.
Please give this a read and let me know where the right place to link is, if not here.
1. You are giving me quality content about your business experiences and decisions.
2. You are giving me this information on a blog supporting a product which, by the way you've crafted the blog post, seems likely to be professional and loved.
3. I'm a person who makes and uses regexps, a HN reader and I want to check out the product. I want to do this easily. The web uses links to do this. You've earned the right to link. It is exactly when you should. It is directly relevant and it is in "your home".
If you are in business, this is why you wrote the blog post. You've got me right where you want me. I'm interested and I have money. Make the path between "he should have my money" and "he has my money" as easy as possible. Link.
Anecdotal confirmation: I probably wouldn't have clicked through (or found it) if the only link was the blog image - despite the first thing I did being to look for the link to the product. (Which is great, and might replace my current 'go-to' for this!)
Bad: The first and last mention of Debuggex in the body text should be a link to your product.