Faldage in September of 2006 noted that a google search in the form Diegogarcity -wordorigins got exactly 2 hits. I just did it today and it’s up to 186. The word by itself gets 1030 and in most uses they credit Wordorigins and sometimes Aldi, thus the coexistence of diegogarcity and wordorigins.
Snowclones by comparison was coined on January 15, 2004 and now gets 213,000 hits.
The coining event for Diegogarcity is in this discussion from 8/23/03 8:18 pm