Old style figures blend invisibly into text.
Old style text figures (or lower case, non-lining numerals) have become popular in graphic design in recent years. Typesetters use old style figures mainly in book publishing and magazines because they are lower case and blend into text, but graphic designers have been largely ignorant of old style figures owing in part to the lack of affordable extended type families in the early years of desktop publishing. For decades now, most numerals in text have been “lining” or “modern” figures—essentially all caps.
Matthew Carter designed Georgia in 1996 for Microsoft’s Web Core Fonts program, and it’s now everywhere online. Why?—because it was included (wisely) in the system software for both Macs and PCs. Web designers preferred system fonts for live type (type which is still editable or can be selected/copied—not a static graphic) so that default fonts (think Times and Arial) would not be substituted for screen display.
Georgia, a lovely, highly readable typeface has handsome old style figures, and since Georgia is now ubiquitous, it has renewed interest in non-lining text numerals. Thank you Matthew Carter, and (dare we say) thank you Microsoft.