I think you might have gotten it a little backwards.
While it's true that the two Speed Demos Archive subdomains in question are hosted at the same IP, there isn't much of a general conclusion to be drawn.
Load balancing in this manner would tend to hurt rather than help persistent connections, as only in the case of SPDY do browsers commonly recognize multiple hostnames resolving to the same IP. (Were this not the case, there would have been no point in domain sharding.) I don't think any browsers provide APIs to override connection management in the way you're suggesting, anyway. As far as I know, none of my examples supports SPDY.
The main purpose of this feature is to be nice to the website owner (the only way in which HTTPS Everywhere cares about performance, and the "best practice" which I mentioned). It is most useful in cases where the same content is hosted on two or more distinct servers, including different CDN providers. Only the Tumblr example demonstrates this. --Eighty5cacao (talk) 17:09, 19 February 2014 (UTC) (+ 22:17, 1 August 2014 (UTC))
I don't treat programming language keywords as adjectives quite as strictly as I do most trademarks, but I do want to make it clear what the reader has to put into a web search engine (such as XMLHttpRequest not XMLHttpRequests) in order to find a definition. I haven't found problems with applying a plural suffix to programming language keywords that are canonically uppercase, such as the keywords of assembly languages, COBOL, SQL, and traditional BASIC. For example, I might talk about SELECTs, INSERTs, UPDATEs, and DELETEs (SQL) in the data access layer of an application or a bunch of LSRs (6502 asm) to retrieve the upper nibble. It gets a little tricker in languages whose keywords are lowercase, especially when the keyword is already multiple words, such as XMLHttpRequest. --Tepples (talk) 16:34, 23 February 2014 (UTC)
"xmlhttprequests"
into DuckDuckGo (with the quotes as shown) shows no shortfall of useful material, though I see what you mean that almost none of the results is a definition. For this query, the 0-click box contains a Stack Overflow result. Note that like most search engines today, DuckDuckGo (and/or the underlying Yahoo/Bing API?) doesn't enforce quotes 100% strictly. I never use Google per se for searching. --Eighty5cacao (talk) 19:18, 23 February 2014 (UTC)
XMLHttpRequest
s) don't look like enough. --Tepples (talk) 02:49, 24 February 2014 (UTC)