EE girls like Vivastreet because
1) you don't have to pay to list a phone number
2) there are no verification checks
3) there are no checks on duplicate accounts
For instance in Lancashire at any given time there are between 90 and 180 Vivastreet profiles, of which 95% are EE girls
Of those, typically 10-15 profiles are of ONE GIRL, a Russian with multiple outcall profiles, each listing a different part of the county. Last time I checked, seven more belonged to another outcall only girl, while thirteen belonged to a menagerie of three (rotating) girls working from a house in Blackburn.
To put it in context, around two weeks ago there around 180 EE profiles on AW (~50) and Vivastreet (~130)combined. When analysed that boiled down to around 90 discrete phone numbers, and 45 addresses. When you take into account that many girls have multiple phones, thats not really a lot. 70 girls maybe?