"scooping (v): publish a news story before (a rival reporter, newspaper, or radio or television station)." Scooping is what happens when another team beats you to publishing results on a problem. Getting scooped is very frustrating and is dreaded by many PhD students. I heard stories about poor Math PhD students who worked on a problem for years only to discover that they got scooped by a couple months.
OK, then what is reverse-scooping? It is a term I coined last year. (Of course, the irony is that after a Google search I discovered that I was almost reverse-scooping someone else ;-). In reverse-scooping, you solve a problem and publish it first. Then several months later, another team (generally from a better-known university) solves the same problem and publish it at a more visible venue. They get all the credit, their work gets cited a lot, and it is as if your work doesn't exist! Congratulations, you got reverse-scooped.
I got reverse-scooped more than a couple of times (obviously I am not going to name publications here). There is no clear definition of same work or similar work, so there is no clear definition of how many times you got reverse-scooped. But it happens, and you know it when it happens to you. Reverse-scooping is often something that could have been easily avoided by doing a simple Google search for the keyterms (or even the title) of the paper. Could it be a simple omission that the offending authors failed to do a Google search and miss your work? That is hard to believe (but I am often generous to give the benefit of doubt). Sometimes reverse-scooping is more insidious: the offending paper cites your paper while seriously downplaying your results. The result is the same, your work will not get the credit and will not get cited further by papers citing this new paper.
Getting reverse-scooped is at least as frustrating as getting scooped. The first few times it happened to me I was very angry. But now I came to find fault with myself when I get reverse-scooped. I take getting reverse-scooped to mean that I should have polished and published that work at the best venue I possibly could. Maybe I should have publicized the idea better and elaborated on the idea further to make my contributions crystal-clear. Reverse-scooping is ugly, and I am not trying to rationalize it. But I find this new way of thinking to be more constructive than getting angry and complaining.