Occasionally I see other users posting links to their own answers or challenges in The Nineteenth Byte. Is this OK? Can I promote my own posts as well?
Promoting your own posts is definitely OK, but there are some very important guidelines to consider. Promoting your own posts is usually OK if
It's relevant to the topic of discussion.
Hey, have we had a challenge about finding the smallest prime larger than N? --User1
Yes [link to own post]. --User2
What's your favorite answer you've ever posted? --User1
I'm really proud of my [hexagony quine]. It took a lot of work. --User2
You want feedback on something.
I'd like to post [this sandboxed challenge] soon. Do you see any problems with it?
I wrote [this python answer], but it seems longer than it should be. Can you see any way to refactor out the for loop?
It's done in moderation. Think of it this way: The less you promote your own posts, the more likely you are to get feedback if/when you do.
This one is a little bit of an edge-case, but it's also fine to promote your own posts if you genuinely think that the users in the chatroom would find it interesting. For example, if you built a working game of Tetris in Conway's Game-of-life. Or if you wrote a "Hello World" program in less than 78 bytes of brainf*ck. Of if you found a trick in Python 3.7 that revolutionizes golfing. All of these are something really interesting (and impressive) and odds are most users would be interested in seeing it.
The rule of thumb to follow is "If somebody else had posted this, would I still really want to share it?" If the answer is yes, then go ahead.
However, you probably should not promote your own posts if:
It already has, or soon will be posted by one of the feeds in the room. Right now, we have feeds for new main posts, new meta posts, new sandboxed posts, new featured posts, new standard loopholes, and new bounties with no deadline. (source) If you have recently posted a challenge, posting a onebox to it 30 seconds later is rude and unnecessary, since it will probably be posted by the feed within 10-15 minutes.
It is to a different site. Unless of course it's directly related a question another user has, for example
Hey, I'm getting this weird error when I do foo in C++. --User1
I wrote an answer about that [here]. --User2
is acceptable, whereas
I just wrote the awesomest answer of all time! [Gimme upvotes!]
I'm having [this problem] over on SO. ANSWER IT FOR ME!
are not. (Bolded and italicized for emphasis)
You have already promoted the same post recently, or many times before. I don't want to set any hard and fast numbers, but if you are sharing links to your posts more than 3-4 times a day, or multiple times in under 20 minutes, you're doing it wrong and annoying other users. Excessively doing this may result in trashing messages, and/or temporary bans.
You act entitled to upvotes. Hey, listen I understand. We all like the little green notification in our browser. However remember, and this is important: nobody owes you an upvote. Votes, up or down, are given out according to the worth of the post, and begging for votes does not make your post any more worthy. Messages like
No love for [my last answer]?
Wow, I put 2 hours of work into [this answer], and I only got two votes?
I'm at 997 rep! Only one more vote needed to hit 1k! hint hint...
are utter garbage, and add nothing to the site, the chatroom, or the community.
None of these are rules per se, but they are very important to consider. In short, before promoting your own posts, ask yourself: "Is this link contributing to the current discussion?" If the answer is probably yes, feel free to go ahead and post it. Otherwise, it's a good exercise in restraint.