Something I've noticed as Chrome is my primary web browser, so I expect plenty of other members will have the same issue.
Last week I noticed that my fonts looked different on all vBulletin forums. This is how it used to look:
However, all of a sudden it started to look like this:
Note that the font size is slightly different and the underlining is messed up so the text appears to join up with the underlining. After a quick google, it turns out this this is caused by an auto-update of Chrome (to version 37).
To fix this, type 'chrome://flags' into your address bar. You will see a feature called 'Disable DirectWrite' - click enable (to disable it, great logic lol).
Close all Chrome windows and re-open the browser. All fixed
Really nice of Google to force an 'experimental font rendering system' onto us by default!