eBay sellers have talked for years about rolling blackouts, "tap-on-tap-off" visibility, "rolling-region" visibility and other strange phenomenon that they say lead to odd sales patterns (see this AuctionBytes blog post from 4 years ago).
Last week, Anne Warrington of Wigs US sent us a graph showing traffic to her eBay store for the past 180 days that shows one of those odd traffic patterns.