I am preparing a survey on Tor and its security. While searching for resources, I have come across with the paper Users Get Routed:Traffic Correlation on Tor by Realistic Adversaries. I comprehend the idea and the conclusion of the paper, but I am a bit confused with the phrase "common locations". Quoting the paper:
Our analysis shows that 80% of all types of users may be deanonymized by a relatively moderate Tor-relay adversary within six months. Our results also show that against a single AS adversary roughly 100% of users in some common locations are deanonymized within three months (95% in three months for a single IXP).
What do they mean by "common locations"?