moar JDOwens feedback. define "combinator". Say RPC. Clarify example'…

…s cache

web/collections.textile

@@ -173,7 +173,7 @@ val result = res1 match {
 
 h1(#combinators). Functional Combinators
 
-Combinators are so-called because they are meant to be combined. The output of one function is often suitable as the input for another.
+Combinators are, roughly, functions that take other functions as parameters and are are meant to be combined. The output of one function is often suitable as the input for another.
 
 The most common use is on the standard data structures.
 

web/finagle.textile

@@ -284,9 +284,9 @@ def isRateLimited(u: User): Future[Boolean] = {
 // Notice how you can swap this implementation out now with something that might
 // implement a different, more restrictive policy.
 
-// Check the cache to find out if user is rate-limited. We find out right
-// away by checking local cache. But we return a Future anyhow in case we
-// need to use a slower system later.
+// Check the cache to find out if user is rate-limited. This cache
+// implementation is just a Map, and can return a value right way. But we
+// return a Future anyhow in case we need to use a slower implementation later.
 def isLimitedByCache(u: User): Future[Boolean] =  Future.value(limitCache(u))
 
 // Update the cache
@@ -314,7 +314,7 @@ This hypothetical example combines sequential and concurrent composition. Also n
 
 h2(#Service). Service
 
-A Finagle <code>Service</code> represents a service that handles remote procedure calls, taking requests and giving back replies. It represents the service's "logic," not the network "plumbing" (but works well with other things that configure that plumbing). A Service is a function <code>Req => Future[Rep]</code> for some request and reply types.
+A Finagle <code>Service</code> represents a service that handles RPCs, taking requests and giving back replies. It represents the service's "logic," not the network "plumbing" (but works well with other things that configure that plumbing). A Service is a function <code>Req => Future[Rep]</code> for some request and reply types.
 
 <blockquote>
 <code>abstract class Service[-Req, +Rep] extends (Req => Future[Rep])</code>