The article is being updated - bookmark it and check back from time to time. Here is the most complete list of sites where you should publish an article about your startup right after product development. 

A list of platforms where regular users can publish. Note that not all platforms allow direct advertising. On most, you will have to tailor the post topic to the site's theme. 

The traffic obtained from publication does not depend at all on how difficult it is. It would seem that publishing in Business Secrets is more difficult, there is editing, and the owner's rating is high - it should take off, but in reality it doesn't. In my experience, a free, unedited article on VC and Product Radar will bring more benefits. 

No Restrictions

On these sites, almost direct advertising is allowed in specific sections, or they do not restrict you at all. 

VC - the "Tribune" section, where you can write about your startup in an advertising format

Tambur - a platform like Reddit, you create a community and then write whatever you want in that community without restrictions. 

Productradar - here you can announce your startup 

Klerk - the theme is stated as finance and accounting, but in reality it also covers legal issues and general business directions.

Habr - formally, you can publish a story about your product in the "I'm promoting myself" hub, but in reality there is a restriction of 30+ karma (which is very high). So it is only formally available to everyone. In free publications, links to your own sites are prohibited.

Dzen - you can write about anything, you are not checked, but getting traffic to an article is very unlikely. 

Telegraph - there is no theme or structure. Your article is simply accessible via a link. But search engines see it. I would use it exclusively for cross-posting.

Glas - a Russian analogue of Telegraph. 

Need to Disguise 

Direct advertising is prohibited here, but links are allowed. You will have to be creative or publish only within your niche. I have managed to publish a site about finding film locations multiple times on all of them. 

DTF - theme: movies, games, comics, books. 

Pikabu - no specific theme, you can write about anything, but the community has a negative attitude towards advertising. 

Vombat - no specific theme, you can write about anything

kapi.bar - no specific theme, you can write about anything

Vuuv - no specific theme, but the site is designed for short messages.

Talkvio - a clone of Pikabu, themes are general and entertainment. 

Tupik - an open platform for personal brand development, quite loyal to advertising posts. 

Spark - marketing and business.

Mel - publication via moderation. 

Sostav - publication with subsequent moderation

Partnerkin  - a site about traffic arbitrage and affiliate networks. Post-moderation, i.e., the material appears immediately, but then it is checked. 

WorkSpace

Yagla - advertising and marketing

Traffic Cardinal - traffic arbitrage

Ucrazy - entertainment theme

Go Through the Editorial Board

This is an advanced level. You need to carefully assess whether you even want to go here, as they require very high-quality content, and the result is not guaranteed, and sometimes they even prohibit direct links to the site. Note that views on some resources are quite low, and I would recommend it more as a brand story, i.e., you understand how to benefit from it. We have removed platforms where you need to write to the editor's email - that is not about openness to external publications. 

Business Secrets - we made a publication about startup planners, passed after minor edits, but we prepared the article for a long time and spent considerable resources.

E-xecutive - you will have to adapt the article to please the editorial board, and the content as well 

Biz360 - Business themes

Delovoy Mir - Business themes

retail.ru - you need to register a company, links are prohibited. 

oborot.ru - publications without editing, but you can only create a channel through the editorial board. 

ppc.world - online business promotion

Connect - business and marketing