/cast .... is used for single spells.
/castsequence ... is used for multiple spells.

A macro will function with or without spaces after the comma's, or at least mine do.
If I use a targeting function in a macro, I personally need a space after the closing bracket or the macro won't run.

Example: /cast [target=party1target] Fireball
Example: /castsequence [target=focustarget] Lightning Bolt, Lightning Bolt, Chain Lightning