[snip]
I'd like to ask that folks leave this thread aside for the moment other than useful replies to the original poster's request about how and where to propose changing $wgSitename for ja.wikipedia.org.
If the code paths for setting up and running the parser to do brace substitution in messages were significantly faster, we wouldn't bother optimizing a few '$1 - {{SITENAME}}'s to '$1 - Wikipedia' on a few of our high-traffic sites with stable names.
Brace substitution in messages is done using a limited mode of the parser, much as it is in templates and wiki pages; avoiding braces in messages that appear on parser-cached pages means that we avoid having to initialize the parser, which can be a very noticeable win on a high-traffic site.
If anyone is interested in actually looking into the costs of Parser setup and invocation for brace replacement in messages and optimizing this code path, that would be great, but please follow up in a new thread and only post _new_ information or questions, not repeats of what's already been said.
Thanks.
-- brion vibber (brion @ wikimedia.org)