Since upgrading to Lion I’ve noticed a font rendering issue with Safari 5.1. Sites were randomly displaying some web-safe and web-served fonts with the Last Resort font, AKA “Block-A Characters.”
These can appear for a variety of reasons, but I was getting them because Safari 5.1 has a compatibility issue when rendering fonts for those who use 3rd party font management apps. I use Font Explorer and love it, but after my old trick of clearing font caches proved unsuccessful, I took to twitter and got some good advice from Jason and Matt. I followed the steps outlined at this CNET post and got an immediate fix. Hooray! Web fonts and font management are still a thing!