-## usage
-
-Here are descriptions of all the supported parameters to the `aggregate`
-directive:
-
-* `name` - A name for the feed. Each feed must have a unique name.
- Required.
-* `url` - The url to the web page for the blog that's being aggregated.
- Required.
-* `dir` - The directory in the wiki where pages should be saved. Optional,
- if not specified, the directory is based on the name of the feed.
-* `feedurl` - The url to the feed. Optional, if it's not specified ikiwiki
- will look for feeds on the `blogurl`. RSS and atom feeds are supported.
-* `updateinterval` - How often to check for new posts, in minutes. Default
- is 15 minutes.
-* `expireage` - Expire old items from this blog if they are older than
- a specified number of days. Default is to never expire on age.
-* `expirecount` - Expire old items from this blog if there are more than
- the specified number total. Oldest items will be expired first. Default
- is to never expire on count.
-* `tag` - A tag to tag each post from the blog with. A good tag to use is
- the name of the blog. Can be repeated multiple times. The [[tag]] plugin
- must be enabled for this to work.
-
-Note that even if you are using subversion or another revision control
-system, pages created by aggregation will *not* be checked into revision
-control.
-
-This plugin is not enabled by default.
-
-[[tag type/useful]]
+The plugin updates a file `.ikiwiki/aggregatetime` with the unix time stamp
+when the next aggregation run could occur. (The file may be empty, if no
+aggregation is required.) This can be integrated into more complex cron
+jobs or systems to trigger aggregation only when needed.
+
+Alternatively, you can allow `ikiwiki.cgi` to trigger the aggregation. You
+should only need this if for some reason you cannot use cron, and instead
+want to use a service such as [WebCron](http://webcron.org). To enable
+this, turn on `aggregate_webtrigger` in your setup file. The url to
+visit is `http://whatever/ikiwiki.cgi?do=aggregate_webtrigger`. Anyone
+can visit the url to trigger an aggregation run, but it will only check
+each feed if its `updateinterval` has passed.
+
+## aggregated pages
+
+This plugin creates a page for each aggregated item.
+
+If the `aggregateinternal` option is enabled in the setup file (which is
+the default), aggregated pages are stored in the source directory with a
+"._aggregated" extension. These pages cannot be edited by web users, and
+do not generate first-class wiki pages. They can still be inlined into a
+blog, but you have to use `internal` in [[PageSpecs|IkiWiki/PageSpec]],
+like `internal(blog/*)`.
+
+If `aggregateinternal` is disabled, you will need to enable the [[html]]
+plugin as well as aggregate itself, since feed entries will be stored as
+HTML, and as first-class wiki pages -- each one generates
+a separate HTML page in the output, and they can even be edited. This
+option is provided only for backwards compatability.