are you talking about doing things like this, while on IRC:

*new post by Random_User in Random Topic
Random_User: Hey guys, check this out ^

buttsfredkin, that is not allowed.
Ephan, enough people aren't obeying it that I'd like to draw attention to it, which I'm perfectly at liberty to do.  backseat moderating isn't allowed either, your comment was out of line.

@Ephan Well the rule was added after some people joined and not all of them read the news, so they could have missed it. It's good to remind people that might have missed the announcment.

I am ok if someone rarely ever does something like that and is like "Runer I'm gonna post my code" | *10 minutes later* | New Post | Ok here is it runer if you're still around", but not plain advertising of project updates.

The reason why it can be annoying is because

1) When 1 person starts doing it, lots of other people does it too.
2) When someone starts doing it repeatedly, it sounds like the person is insisting/begging so everyone stops what they're doing and immediately check their new project update, like if only themselves were important.

I am personally ok if someone says I posted a new screenshot on the forums when the bot is down, though, as long as it's not repeated.

Yeah true, or when it's a post that you told you would make or has a title that might mean many things. Just don,t go like "Check my topic now!!1!!!1!1!one"

Also now it's worse to advertise a topic on OmnomIRC because of a recent OmnomIRC glitch that causes certain people's lines to appear several times every few minute, so some admins might think you're repeatdely doing it

That is fine. If it has been several hours I recommend double posting, though, because then if the edit occurs while people are busy, your topic won't be bumped in the posts list.