What does "reserved" mean when someone posts it on a mod thread
 

Sometimes people ost reserved on mod threads. What does it mean?

That's just so the author/developer can use the first few response posts to give more information later without his post showing up at position 50 or 100

Exactly. Sometimes during future development of a mod, a developer may want to add info, but the first post is to long, or they can not add any more attachments to the post, so by reserving the second post, this allows them the ability to add more info as needed. :)

Does anyone ever use it? I get the idea that it's something that someone thought was a good idea at one time, so everyone started doing it. I don't know, maybe I just don't get it. But I think if I had something important to add I'd put it near the top of the first post, and in red, because some people don't even read through the first post as it is. :)

Well like I said, sometimes you need to add more attachments, but we are only allowed ten, so you would need to add anything above that in another post.

I've used it several times, even if the 2nd post remains Reserved" for 1+years or more I've come back a year or so later and edited to include pertinent info. Typically I reserve post 2+3 or in the least post 2... what to place there? Common questions and answers... after several pages of support you can copy/paste the most frequently asked questions and issues for someone to find easily in post #2. Also make a note in the actual mod description and link to post #2 stating that more information and pertinent info on issues are there (since the first post of a mod thread is at the top of all pages, therefor if they click on a forum link taking them to page 37 of a mod thread, when they see the mods post at top of page 37 it links them to post #2 respectively).

Edit: Sadly sometimes they do not read, oversight... kids coming into the room asking them questions... heck maybe their at work but point is no one tends to read the fine print so BOLD it, RED it whatever you feel is necessary to make them notice something you deem important.

I've used it, too.