Former Google VP Kai-Fu Lee Got a Nickname, Start-Copy Lee
Some other important look-and-feel clones:Windows (copying MacOS)Lotus 1-2-3 (copying VisiCalc)GNU/Linux (copying Unix)Gosling Emacs (copying ITS and Multics Emacs), which eventually became GNU EmacsExcel (copying Lotus 1-2-3, to the point that VisiCalc slash commands still work in Excel last time I tried them about five years ago)OpenOffice (copying Microsoft Office)C compilers everywhere (copying the original Unix C compiler)Compaq's clone PC (copying the IBM PC, and giving rise to the entire IBM-compatible market)Friendster (copying Sixdegrees)Facebook (copying Friendster, somewhat less faithfully)Every modern IDE (copying Turbo Pascal)Every modern search engine (copying Google)MS-DOS (copying CP/M and a little bit of Unix)MercadoLibre (copying eBay)Intel's current x64 CPU line (copying AMD)Netscape (copying Mosaic)Internet Explorer (copying Netscape)Wordpress (copying Movable Type) (I'm not sure who to credit with the modern blog, with its comment threads, "after the jump", and permalinks. Pyra?)Being able to copy the look and feel of competing products is crucially important to allowing innovation to continue. If Personal Software Inc. still had a monopoly on spreadsheets, it's a good bet that the spreadsheets we use today wouldn't have progressed much from where we were in 1984.  The interface designs that seem innovative and unique today are either faddish crap or the baseline from which tomorrow's innovation begins.