Just now I did some hacking of TikiWiki on the LAKA site. First I added a feature - now RSS feeds from news articles can be selected by topic. Then I put two rss aggregators on the main Wiki page of the site - one with all articles on 'LAKA' topic and the other one for all articles.
In the process I discovered a bug in Tiki RSS lib that did not allow two RSS feeds to be put on the same Wiki page. I traced the call to a 'include()' directive that should have been 'include_once()'. This also caused another bug to appear there - variable $rsslib had to be declared global in the same module.
Now I only have to create some way to make a feed for 'all topics except LAKA'. That will be harder.

PS. Restoring Mailman and Postgresql was a snap. Today seams to be a better day for me :)