A few days after the Paris terrorist attacks, Dina Temple-Raston of NPR reported that French authorities “were very focused on trying to abort a second attack. And they’re worried another one, a follow-on attack, will happen.” That night, I heard Rachel Maddow use “follow-on” the same way in her MSNBC broadcast.
Not being familiar with the term, I looked it up in the Merriam-Webster Dictionary and found this definition: “being or relating to something that follows as a natural or logical consequence, development, or progression.” It would seem a useful term, but the origins are murky. The OED reveals a cricket etymology for “follow on,” starting as a verb referring to a side that “go[es] in again at once after completing the first innings, in consequence of having made a prescribed number of runs less than their opponents in the first innings.” (I can only assume that that sentence makes sense.) The dictionary quotes an 1865 cricketers’ guide: “Surrey ‘followed on’, but left only 23 runs for Oxford to get to win.”
The first non-cricket use cited by the OED is from a 1960 advertisement in “Farmer & Stockbreeder”: “This new booklet contains advice about ‘follow-on’ feeding.” Not sure what “follow-on feeding” would be, or how it followed (no pun intended) from the cricket term.
Non-cricket “follow-on” was subsequently picked up in various contexts, maybe most commonly in the business term “follow-on effect.” I feel that it’s mainly been a Britishism, but at this point I am unable to say for sure. I can report, however, that the the majority of the results in a Google News search for “follow-on effect” are from Australian sources.