Datedness of Daria
As with any television show there are specific elements that tend to limit the show to a certain chronological period. Daria is no exception.
The argument could be made that any movie, television show or media creation becomes dated as technology, fads, and other products available at the time it was produced are by necessity reflected in the final product. An exception could be made for programs that deliberately try to recreate a bygone time period, or to evoke nostalgia. One would expect that that a movie made in the 2000s about the 1960s would reflect the lifestyle of the time.
Further arguments could be made that too much importance can be placed on time-specific elements and not enough importance on the exploration of universal truths that give movies and TV relevance beyond the time period of their immediate creation. However, there are certain parts of Daria that tie it to its time and place.
General Limitations
None of the characters have cell phones, which are ubiquitous today. Only one cell phone is seen in the series, in The Teachings of Don Jake, and it is a very large bulky device unlike the cell phones of our era.
Quinn carries a beeper, when she would carry a cell phone if the show was set in the modern era.
Jake is confused about the comic strip B. C. and its religious elements. Johnny Hart, the cartoonist for B. C., died in April 2007. As of this writing, it is unknown who will continue B. C. The new artist might continue writing the strip from Hart's religious perspective.