A Funny Times cartoon (passed on by Rebecca Wheeler on Facebook):
In the world of innovative quotatives (which includes go, (be) like, (be) all, and be), (be) like has definitely been on the upswing. See the items in Isa Buchstaller’s 2004 bibliography on quotatives: social and linguistic factors and grammaticalization and the Stanford papers on quotative (be) all:
John R. Rickford, Isabelle Buchstaller, Thomas Wasow, & Arnold M. Zwicky. Intensive and quotative all: Something old, something new. American Speech 82.1.3-31 (2007).
Isabelle Buchstaller, John R. Rickford, Elizabeth Closs Traugott, Thomas Wasow, & Arnold M. Zwicky. The sociolinguistics of a short-lived innovation: Tracing the development of quotative all across spoken and internet newsgroup data. Language Variation and Change 22.2.191-219 (2010).
From the abstract for the second of these:
This paper examines a short-lived innovation, quotative all, in real and apparent time. We used a two-pronged method to trace the trajectory of all over the past two decades: (i) Quantitative analyses of the quotative system of young Californians from different decades; this reveals a startling cross-over pattern: in 1990/4 all predominates, but by 2005 it has given way to like; (ii) Searches of internet newsgroups; these confirm that after rising briskly in the 1990s, all is declining. Tracing the changing usage of quotative options provides year-to-year evidence that all has recently given way to like.