Edited sentence: Sony has made use of vertical product tying, an anti-competitive practice:.The Playstation 2 featured only two controller ports despite other consoles of the time having four.The company's Memory Stick Duo is not directly compatible with an SD card or USB port but requires a special card reader to be purchased separately.This severely impacted Sony's reputation amongst the gamer community; Lik-Sang was widely regarded as being the best place to import games from Japan.Use use of four controllers with the PS2 required the purchase of a Sony multitap device