http://www.pcgamer.com/destiny-2s-seasons-have-been-explained-sort-of/

We're gearing up for Destiny 2's PC release on next week. In addition to the full review once we're happy with how the servers are functioning after the 24 October launch, we also have a bunch of guides in hand to help you level up and get raid ready. Among those you'll find multiple benefits to being in a clan. Today, at Twitchcon, Bungie went into more detail about how 'seasons' will affect clans, and how the game's live team will seek to keep the game fresh with content updates and special events.

Seasons enable clans to unlock shared perks for completing weekly objectives, such as completing the raid or going flawless in Trials of the Nine, alongside their clanmates. Perks involve stuff like receiving additional loot drops or resources from other activities. According to live team game director at Bungie Ryan Paradis, four seasons are planned for the first year of Destiny 2, and each shift will be marked by a major patch that tunes the gameplay sandbox (ie rebalances weapons and abilities).