i know synergies only benefit from hard points, but i heard something about certain synergies benefiting from plus skills. is this true? i'm talking about something like cyclone armor's +2 sec duration for hurricane
When synergies were first unleashed a skill would get synergy bonus from +to skills if there were NO hard points in said synergy skill (skill granted by item). Marrow was a perfect example because of its great bonuses to the Bone spear/spirit synergies whic made the Boner so popular in .10
There's nothing special about hurricane and cyclone's synergy relationship.
Perhaps you're refering to the prayer, skeleton mastery, and druid summoning "synergies". These aren't true synergies, as they worked the same way before synergies existed (at least the summons anyway), but when synergies were put in the "This skill recieves bonuses from" phrase was put in the skill description in green text.