Yup, pretty much. A trio of Spolsky/Atwood posts from 2007 worth reading:
http://www.codinghorror.com/blog/2007/06/whats-wrong-with-ap...
http://www.joelonsoftware.com/items/2007/06/12.html
http://www.codinghorror.com/blog/2007/06/font-rendering-resp...
Ubuntu does not install Microsoft fonts by default. It will fallback to Ubuntu's default font.
(Like, a half hour ago, I checked that Verdana was installed and then recreated the screenshot from the original post and it's identical as far as I can tell.
Right-click the text and choose "Inspect element". In the right-hand column, make sure "Computed" is selected at the top, then look to see what font-family is being rendered. (If you click "Rules" at the top, you can see which rules are active.)
The '3' doesn't look any more different than other chars due to rendering difference, to me.
And KDE's font manager's take on Verdana: http://i.imgur.com/4c5cSe3.png
And Firefox on my system, just as a reference: http://i.imgur.com/a2yZ7UQ.png
There are differences with how the text is rendered. Maybe it has to do with kerning and subpixel optimizations.