tap abilities activated abilities difference magic

[ralphy99]

whats the difference between tap ability and activated ability?

[Void Elemental]

Activated abilities are recognizable by the "Cost: Effect" setup. "Tap abilities" are such abilities (ie. Crystal Shard).

[Arix]

As far as the rules are concerned, there's no such thing as a "tap ability". That's just unofficial slang that players use to describe an activated ability with a tap in the cost.