Do you know that the minimal font-size that can be set in CSS and will be supported by Opera is 10px? I mean that font-size: 8px;,font-size: 9px; and font-size: 10px; will look in Opera the same. Not a good thing for a good browser I think. Firefox supports even 1px (of course, you’ll read nothing, but it supports that!). Internet Explorer also supports font-size of 1px as well as Apple Safari does. Google Chrome does too. So here is a table that accumulates these data. If I have experience with new browsers, I’ll extend the table.

Maybe Opera’s purpose was just to make the life of black hat search engine optimizers more difficult?