What is crowd testing

U-test provides service call it as “crowd sourced” testing model with a global community of professionals.
The community reflects the diversity (e.g. multiple geographic locations, languages spoken) of the apps and users themselves.

We can consider it as user satisfaction testing because testers might come from different countries with different Operating systems ,real devices and real network conditions.
And at the same time we can consider it as exploratory testing as well because they are exploring an application without having predefined document and finding a bugs.