People don’t read or care about those little blurbs that explain what a score means. As Ben says, people are accustomed to having seen both 5 star and 0-100 scores in many other contexts, and evaluate scores accordingly.
To me, 0-100 (and 0.0 to 10.0) map directly into grade school scoring. Anything below 60 is failing (quite bad). Anything below 80 is essentially poor. And unless you’re hard up for a given genre, you really shouldn’t much consider anything below an 85.
Most magazines/web sites reviewing on this scale have 80%+ of their games in the range of 60-93.
On a 5-star scale, anything below a 4 is considered something to avoid. The only ‘check this out’ scores are 4, 5, and 4.5 (if they have it).
It would be nice if Gamerankings tweaked their translations of 5-star scores into 100 point scores. It would be nice if they had a sliding scale per site, that adjusted for each sites tendency to score games a bit higher or lower than their peers. But this adds complexity, and really doesn’t add much value to their final composite scores - For any game with 12+ reviews (i.e. all major games), the scoring subtleties of individual sites and systems get averaged out.
That said, as a developer, I was certainly frustrated by the 5-star systems, as you are much more likely to get a 3 or 4 star rating, which translates about 10 points lower on the 0-100 scale than if the game were scored directly on the latter system (at least the way most sites seem to distribute their scores).
Finally, on a mostly unrelated note, I was watching that ‘Skating with Celebrities’ show (yeah, go ahead and mock me). They generated 6 scores per skating pair - 3 judges each giving an ‘artistic’ and ‘technical’ score. Despite huge variations in the performances (Tod Bridges could barely skate. Bruce Jenner was about as artistic as, well, I would be on skates), every pair got a score between 7.8 and 8.3 from every judge, down to the last pair, who was actually quite good technically and artistically, and really broke through to something like an 8.5 average. Basically, they were using 5-7 points of a 100 point range.