(Matthew Roth,
Global Communications Manager at the Wikimedia Foundation, taught me that at Wikimania).
It is possible to *target* a post to a single Country, or Language (or other "dimensions").
This can be really helpful for a linguistically diverse community as ours: every ws admin could promote the collaboration of the month just to his language community, or country.
You can go here and read this how-to:
You’ll see the cross-hairs icon in your status area. To start narrowing your target, just click on it and then click Add Targeting. Note that that the post will still show on the Wikisource timeline to all users.
It's time to flood the world with Wikisource posts :-)