From BBC News this morning:
http://www.bbc.co.uk/news/uk-11250835
A former Pokerstars employee, speaking anonymously to the 5 live Investigates programme, said that the site's rapid expansion caused problems.
"We had a hard job keeping up, just because of the volume of complaints from players [about suspected cheating]," he said.
"Not that all of the complaints were legitimate - 95% were just bitter [customers] because they lost, and there was no collusion. But Pokerstars still pledged to investigate them all."
However, the former employee also claims that during his time working for Pokerstars, staff switched off the automatic alerts that flagged up possible cases of collusion because they were so overwhelmed by the number of alerts popping up.
Pokerstars did not wish to comment on the claims made by their former employee.