EDIT: Just use ssokolow's solution:

2329388

2329120 LEL

y u no include http*://fimfiction.net/*

2329245

You are heppeh now?

2329259 Jawohl

2329269

Do you have adblock? If you do then the ads have been replaced with text talking about the ads.This removes that.

2329120
I'm still new to Greasemonkey, so I'm not exactly sure what I did correctly to get this operational, but it does seem to work, thank you.

2329269

It hides the rose-colored "Please unblock ads here" bar that was just added between each chapter and its comments.

However, you don't need a full-blown userscript. You can get the exact same effect with less overhead by just doing this:
1. hit Ctrl+Shift+F to open AdBlock Plus's filter preferences
2. Click the "Custom Filters" tab
3. Click the "Add filter" button
4. Paste the following into the text field which just appeared and press Enter

fimfiction.net##*.likfhlskdhslikdf

The syntax for writing custom AdBlock Plus rules is explained on their website if you're curious.

...or, if you want to do it using Stylish rather than Greasemonkey or AdBlock Plus:

@namespace url(http://www.w3.org/1999/xhtml);

@-moz-document domain("fimfiction.net") {
.likfhlskdhslikdf { display: none !important; }
}

I'd go with the AdBlock Plus version if you're already AdBlock Plus since that'd have the least impact on page load times when your browser is loaded down enough for it to matter.

(Now, of course, Knighty could always start an arms race, in which case the description of how to identify the notification would have to be done via Greasemonkey but, given what the message says, I doubt that will happen.)

2329120

is there any place I could go to to learn some of this code? Like how to code.

Gah, this moral conflict... I hate ads, but I feel like a dick for intentionally avoiding to support this site. Damn.

2329607
There are several information sites such as W3 School. However, most of it probably comes by trial and error, because that's how I learned everything I know.

2329388

This would have been nice to know earlier. I glanced at Adblock Plus's filter options, but without knowing the syntax, or bothering to look it up, it didn't appear to do what I wanted. A Greasemonkey script was the most obvious way for me to do it at the time.

2332089

I learned it was possible years ago when I stumbled across this extension which adds a GUI for it:
Element Hiding Helper for Adblock Plus

2329607

Check out the resources I posted for someone else in the Requests & Ideas thread.