Depends on the font. WebmasterWorld is using 2, but it's using Verdana as the family, which is a larger font to begin with. Three, at least on Arial, appears to be equivalent to 13 or 14 pixels. I don't necessarily know that having it on 2 is affecting you, as it appears to be 11 or 12. But if your audience is having trouble reading the words and backing out of the site, I suppose it's possible.
On a sidenote, I didn't realize so many sites still use the font tag.