I often see the expression "briefly noted" on weblog posts (and also New Yorker). In general, what does it mean to say "something is briefly noted".
To "note" something is to recognize and then acknowledge or comment on it. To do something "briefly" is to do it for a short period of time. (Or, in reference to saying or writing something, to do so concisely or using only a few words.)
If something is "briefly noted", that means that one is only saying a little bit about it rather than describing it in depth.
"Briefly Noted" is usually a category of "shorter than usual" articles in a magazine or other long-form publication. If the typical article is 1200 words, a "briefly noted" article might be 600 words or less.
For example, in the Pennsylvania Gazette Briefly Noted section, there are only two or three sentences about each topic. A typical feature story from the same publication is much longer—fifty or more paragraphs.