From 2007 to 2013, the logo for blogging platform Tumblr was Bookman Old Style with vary little adjustment. Considering that Bookman dates back to 1860, the mark looked remarkably contemporary. The glassy fill and occassional bubbly outline had something to do with that, but even without the effects it felt pretty fresh. Chalk it up to a super-tight, all-lowercase setting.
Around the time of their Yahoo! acquisition in mid-2013, the company refined its logo, redrawing the letters for an even tighter, more customized fit. The ‘t’ was narrowed, the ‘u’ lost its leading serif, the arm of the ‘r’ extends just a bit further, and the ‘u’ and ‘m’ curves were given a smoother connection to the stems, resulting in rounder (perhaps friendlier) counter shapes.