Can you multiclass in 4e?

Could you elaborate on the concept of multiclassing in the context of the 4th edition of Dungeons & Dragons, and what specific rules or mechanics does it entail? I'm curious to know if this system allows players to blend different class abilities and if there are any limitations or requirements for pursuing such a path. Furthermore, are there any strategic advantages or disadvantages to multiclassing in this edition that players should be aware of?