Add clarifications to CONTRIBUTING

In particular, this commit discusses what sort of resources I _won't_
accept, and why.

Author: Michael0x2a

CONTRIBUTING

@@ -2,16 +2,45 @@
 
 Thank you for contributing! 
 
-You can contribute by either creating a pull request or by filing an [issue][is] on the issue tracker. In general, try and keep to one suggested change per pull request/issue. It's easier to work with a series of many small suggested changes rather then one large suggested change.
+You can contribute by either creating a pull request or by filing an
+[issue][is] on the issue tracker. In general, try and keep to one
+suggested change per pull request/issue. It's easier to work with a
+series of many small suggested changes rather then one large suggested
+change.
 
 When suggesting a new resource or link to add, be sure to...
 
-1. Include a link to the resources and a brief description or annotation.
-2. Make sure the resource is high-quality
-3. Try and avoid overlap or too much redundancy between existing resources.
+1.  Include a link to the resources and a brief description or annotation.
+2.  Make sure the resource is high-quality
+3.  Try and avoid overlap or too much redundancy between existing resources.
 
-The goal of this collection is to create an annotated list of high-quality resources suitable for beginners or people wanting to improve their skill in an existing category. This collection is **not** meant to be an exhaustive list of every single possible resource, since that might be overwhelming for beginners. 
+In addition, please keep in mind that at present time, I will generally NOT
+accept:
 
-In addition, if you feel that two existing resources are very similar and that having both of them adds no value, or if one resource is too low-quality, please open a discussion on the issue tracker. 
+1.  Resources specific to a particular library or framework.
+
+    Currently, this resource is more oriented towards collecting resources for
+    learning programming languages. I unfortunately don't have the time to do a
+    thorough evaluation of all the different popular frameworks currently in use.
+
+2.  Content which can only be accessed through payment.
+
+    I _will_ make multiple exceptions to this rule, especially for books or
+    for paid content which has a good number of positive critical reviews.
+    Basically, I need some way of verifying that a given resource is
+    high-quality, either by reading it myself or by relying on reviews by
+    others.
+
+Please note that the goal of this collection is to create an annotated list of
+high-quality resources suitable for beginners or people wanting to improve their
+skill in an existing category. This collection is **not** meant to be an exhaustive
+list of every single possible resource, since that might be overwhelming for
+beginners.
+
+In addition, if you feel that two existing resources are very similar and that
+having both of them adds no value, or if one resource is too low-quality, please
+open a discussion on the issue tracker. 
 
   [is]: https://github.com/Michael0x2a/curated-programming-resources/issues
+
+