user41036: I developed an android app (game) that helps students memorize Neirenberg codon table.
May I advertise my biology-learning app on meta or Biology Stack Exchange?
Or is it off-topic?
 The app homepage is here 

user3340: There are community promotion ads. If you think your app would be useful to others then you can put up a request for an ad there. The community will decide, by voting, if it is useful enough to be displayed on the site.
You may use the comments to explain what the ad is about or discuss with the members on the chat. 

user5144: Thanks for asking, but you may not. This will be seen as spam and treated as such. 
And if you argue that your app is free: Where should we draw the line?
This site is for asking and answering questions about biology, nothing else.

41036: <p>I developed an android app (game) that helps students memorize Neirenberg codon table.</p>
<p>May I advertise my biology-learning app on meta or Biology Stack Exchange?</p>
<p>Or is it off-topic?</p>
<p> <a href="https://kyhsgeekcode.github.io/CodonDalma/" rel="nofollow noreferrer">The app homepage is here</a> </p>
 3340: <p>There are <a href="https://biology.meta.stackexchange.com/questions/3784/community-promotion-ads-2018">community promotion ads</a>. If you think your app would be useful to others then you can put up a request for an ad there. The community will decide, by voting, if it is useful enough to be displayed on the site.</p>

<p>You may use the comments to explain what the ad is about or discuss with the members on the chat. </p>
 5144: <p>Thanks for asking, but you may not. This will be seen as spam and treated as such. 
And if you argue that your app is free: Where should we draw the line?</p>

<p>This site is for asking and answering questions about biology, nothing else.</p>
