Re: Update permalinks in activity stream
I agree – of course ensuring that the main keyword is prominent in url, title & description is a good thing; that’s one of the ways SEs determine the relevance of content… and up goes the pagerank 
(Otto does come off as being a “bit” opinionated on that point, doesn’t he?)
But he does illustrate a valid point about performance and WordPress’ rewrite rules. Here’s an interesting discussion on trac about URL routing, and how to improve same (over my head, but interesting nonetheless):
https://core.trac.wordpress.org/ticket/12935
