This site, AskUbuntu.com, uses the "UbuntuRegular" font. Sometimes the font size is 14px, which displays fine, but in the "comments" (& perhaps other places), the font size is 13px, which cuts off the bottom of low-hanging chars.
Here is a screenshot of the string "testing 123 abcdefghijklmnopqrstuvwxyz" as a comment, in various sizes...
Notice the "g", "j" & "y" have the bottom cut off in sizes 12 & 13px.
Here is a screenshot of the letter "g" (from the word "testing" in the screenshot above) in 13px & 14px, pasted in Paint, zoomed to 800%, grid turned on & then another screenshot taken of that...
The "13px" g is really in an 8px by 11px "box" (with 1px whitespace around it — not based on actual "character box" size, since I don't know where it is from a screenshot).
At 1st I thought it was a line-height issue, but then, after ruling that out, I noticed it's a font problem. The "UbuntuRegular" font simply don't render well at 12px & 13px.
This bug really needs to be fixed by someone editing the "UbuntuRegular" font...however, AskUbuntu.com could workaround the issue by making comments either 14px or 11px...or using a different font.
Note: please see the revision history for what I went thru to report this!