The problem with an OnlineDiary is that this concept does not scale up to users of several wikis. If you started a diary on Meatball, but then started working on some other wiki, you don't want to add diary entries to both. This is where RichSiteSummary (RSS) inclusion comes in. You maintain your own homepage, and provide an RSS feed. Then you include the RSS in your homepages on the various wikis.
Since the changes do not show up on recent changes of the various wikis, this solution is not optimal, either. It only scales to a few people on every wiki. Once you determined the two or three people whom you like, you can check their RSS feeds and see what they have been up to. But since you are not offered the news directly while browsing the wiki (as a RecentChangesJunkie), you are not exposed to the private lives of your peers that often.
Recognising new entries in RSS feeds and including them in RecentChanges is no good, either, because people will disappear from a wiki, but their RSS feeds will continue to bring up news. But if the people are no longer part of the community, the RSS feed should be quiet as well.
It is therefore unclear, whether RSS inclusion actually solves the problem. Perhaps the optimal solution is this:
Have an RSS feed as described, not shown on RecentChanges, and *still* add specific news manually as appropriate for each community. Then, when things happen that are of interest to the rest of the community, it will show up on RecentChanges, and if people then want to see what else you have been up to, they can follow the links of the RSS feed.
Seems like the thing to do is just publish the URL for your blog on the wiki. If people become interested in you and what you're doing they will "subscribe" to your blog with whatever they use to do such things. -- http://www.lathi.net/
David is right. I think RSS inclusion for wikis are a failure. Providing RSS feeds is a good idea, including them on wiki pages isn't. I use them on homepages on other wikis  . But I don't think anybody reads them. If somebody stumbles upon my homepage on another wiki, they would also follow a link if they want to read more about me. If they are interested in regular news, they will use the RSS feed of my site -- not the RssInclusion on some wiki. RssInclusion therefore does not solve the original problem: How can we get to know each other better? This is what an OnlineDiary does. But it doesn't scale. As soon as you participate in several communities, you can't keep your online diary on only one of them. Thus the important tools are RSS feeds, and a ChangeAggregator. RssInclusion fails because a wiki posing as a ChangeAggregator is just a bad aggregator.
RssInclusion does offer the advantage that you can use a wiki to build your own portal. HansruediHaenni argues on IC4 that nomads prefer web-based news aggregation  accessible from anywhere, anytime. This solves the following problem:
For me RSS includes have been very important. I'm interested in trying to persuade people that wiki is a good front-end (or dashboard) for a complex information system. (It's good because a community of users can configure / organize it in a way that suits them. And annotate it with the documentation needed for new users to understand and navigate it.)
It's normally when I demonstrate RSS includes in pages that they "get it". Wow! Anyone can just put the feeds together the way they want.
(Of course, it may be that the RSS include is a heavy feature for the OddMuse script and might be better refactored into a separate package and included on wiki pages with standard raw includes. )