The Activity plugin lists pages found in sitemaps retrieved from federated wiki sites mentioned on pages you have visited. These sites comprise your search neighborhood.
See About Activity Plugin for an example use.
See About Activity Configuration for customization details
See GitHub 
for plugin source.
Pages are listed in a compact variation on References. The flags in front of each page name indicate where that page has been found.
Click a flag to retrieve the page from a specific server. Click the link to retrieve the page by wiki's usual rules.
Flags show without space when two sites have pages with identical revision dates.
It is possible for two sites to have identical page dates when pages are, say, published by copying a database. A space between flags means that there is a date difference indicating that some new change can be published.
Wiki takes a few seconds to load each sitemap so it can get behind. You can see wiki working at this by noticing the flags in the web page footer.
The server dates the pages as the sitemaps are loaded. More recent changes can go unnoticed until the sitemaps are loaded again.
The plugin interprets data that is loaded in the course of browsing. It updates as new information becomes available. For the newest information, reload the whole web page, not just the wiki page with the Activity plugin.
See About Changes Plugin to list changes kept in browser local storage.
Related How Tos
The wiki keeps track of sites you visit and sites mentioned on pages you visit on each site. Wiki seeks to know about sites in this collection called a neighborhood.
Search looks at the title and first paragraph of all pages in your Neighborhood. As you browse the federation more sites are added to your neighborhood so search can find more pages.
You can add references to other Federated Wiki sites. Here we show what a reference looks like.