Certainly it seems safe to suggest that Google reader could - and perhaps should - influence personalised search.
I think I was one of the first to break the news that Google Reader had been updated. I'll note that because it'll rarely happen. This isn't a "news first" blog. This is my rants and raves blog. I saw the chance to be quick with news and so I took it.
Some time later the brain begins to work. I do this often. Sometimes the penny can be slow to drop. I knew all this already.
What we see on the trends report on Google Reader is that Google isn't just recording which RSS feeds I subscribe to (which is an indication that a human just voted for the quality of the site) but it is recording what percentage of the articles I read.
If I ignore an RSS feed then Google could notice.
If I ignore AdWords what happens? The quality score goes down and the advert begins to slip in position. It wouldn't be impossible for Google to note which RSS feeds got read (implying good content) and which did not.
Anyway... here's an idea. Do you know what would be cool? Being able to integrate your subscribed RSS feeds in reader.google.com to Google News. When I'm searching Google News and I use keywords which have also recently been mentioned in my Google Reader then it could let me know.