Hi Eneasz, I'm not sure what controls the front page map. My guess would have been that posting the meetup to the regular meetup system would be enough, perhaps there's a delay.
Please include the meetup location (Utrecht) in the meetup names, ideally at the beginning. Otherwise people have to click through in order to determine if the meetup is relevant to them. Thanks!
The best way to announce it is to click the "Add new meetup" button, right under "Create new article". Every Friday morning (around 9 AM PST) I scan the list of upcoming meetups and add them to the weekly summary.
Cool. When the a regular meetup is included in the list I make it a link to an entry on the wiki meetup page (e.g. https://wiki.lesswrong.com/wiki/Less_Wrong_meetup_groups#Hamburg.2C_Germany). I don't see one for Cologne, can you or someone else in the group create an entry?