To improve search results internal on the site, including the tag links, I have just started re-indexing the search database for the whole site.
This is done by resetting (deleting) the current search database. And with almost 200000 posts, this is not done in an hour or two. I estimate that it will take 2-3 days before everything is re-indexed. So the best time is over a weekend.
I will post an update to this post, when the indexing has been completed.
Don't forget to "Verify Solution" the post(s) that solved your problem. This credits the experts who helped, earns you points and marks your thread as Resolved so we all know you have been helped.
Forgot to post the update. All posts have now been reindexed.