NPR | Grammar Girl
Spurred by a biology professor's request that NPR use the word "data" as a plural noun -- "datum" being the singular -- NPR's Lori Grisham researched how the word has been used on the air:

The good news for [professor Robin] Taylor and other language traditionalists: the plural use is not completely extinct. The phrase "data are" appeared in 17 stories. The bad news: "data is" appeared in 39.

As Taylor himself said, languages are alive and change over time. It appears to our office, however sadly, that this is one of those times.

Grisham notes the AP Stylebook's guidance: Data usually is used as a plural noun, but it can be singular, too -- depending on whether the writer is referring to an individual data point or the collection of data. But, as ProPublica's Scott Klein asked last week on Twitter, "When are you ever not referring to it as a unit?"

Grammar Girl provides a guide:

If you wish to use data as a singular mass noun, you should be able to replace it in the sentence with the word information, which is also a mass noun. For example,

Much of this information is useless because of its lack of specifics.

If, however, you want to or need to use data as a plural count noun, you should be able to replace it with the word facts, which is also a plural count noun. For example,

Many of these facts are useless because of their lack of specifics.

Klein's reaction to the NPR post: "Gotta go with Grammar Girl on this one. You wouldn't say 'these bacon are delicious.' "

Let the debate continue. || Related: Misspellings show language’s evolution, but does that mean they’re OK for journalists to use? (Poynter)