What I did was add a text box to the preferences page to allow users to specify, using a regular expression, the categories for which they were interested in getting email notifications. In the saved text i look for text like [CategoryBlah?,CategoryBlah?1]. Then I match this list of categories with users who subscribed for them and email out appropriately. I also added a [cc: email] syntax that forces email notifications to certain people. I think a nice feature would be to allow actions to be associated with patterns found in each line of submitted text. This way it would be easy to add new capabilities based on tokens embedded in the text.
See also JspWiki:NotificationList.
MediaWiki gives users "watch lists" which are SubscribedChanges.
The purpose of this feature, I assume, is to save yourself from spending too much time on issues you do not care about. Does the feature deliver what it promises to do? If it does not, then in addition to not doing what it promises, it would only waste more of your time, since you will be checking RecentChanges anyway. I assume the feature also has some drawbacks, such as less PeerReview. I think that the real problem is that there are too many different issues being discussed on the wiki, so that there is no longer one community, and based on the good experience I have had with dedicated wikis (MeatBallWiki, UseModWiki, EmacsWiki) and the bad experience I have had with general purpose wikis (WikiWiki), I think the real solution to the problem is that you need to split your community. See WikiSubcommunity for further discussion.
Example: If you are interested in Artificial Intelligence, you will find some pages on Meatball. But in the end, they just distracted from the real topic -- online communities -- and now the people that are really interested in this started their own, dedicated AiWiki.
Many people keep blogs (see WebLog), and when they join a wiki community, instead of starting a new OnlineDiary, they just link to their blog.
How do you notify members of the new online community you joined about changes to your existing blog?
The problem with all these solutions is that changes to your blog will not show up as changes on the new wiki; had you used a new OnlineDiary on the new wiki, your changes to the diary had shown up on the wiki.
Wikis trying to incorporate blogs is an interesting change from blogs trying to incorporate wikis. Perhaps a better answer would be to have SubscribedChanges create an RSS feed. Is it really important to have an RSS entry for each diary entry, or just have a UnifiedRecentChanges including your friends' diaries on other wikis? I've been thinking about this (both the input and output sides) for a little while. I'm not sure I want to make the system that complicated, but it seems like a good InterWiki move. -- SunirShah
In this particular case, it was important to have an RSS per site, because people have a home-"site" with many pages, and want to link the recent changes on their site from their home-"pages" on the various wikis. RSS inclusion does just that. -- AlexSchroeder
MediaWiki has [watchlists] that allow users to monitor changes at a selected group of pages in the wiki.