I don't remember which version was out in 2014, but one of the newer features is that you can send squads out to raid other sites.
Did you play the 2014 release or stop before it? The game has had massive changes since then. 3 major releases. You're better off reading the devlog.
Invaders jump, invaders climb, trees are big, the outside world is active as you play, adventurer is almost a real game, gather fruit using stepladders. Retire fortress and come back later.
Taverns, libraries, temples attract visitors, non-dwarves join your fortress as mercs/entertainers, animal men (and plump helmet men and gorlaks) can join civilizations. Everyone from a human, dwarf, elf civ is playable in adventurer (including the goblins who live there and aforementioned animal people). Adventurer built sites. Alcohol poisoning.
Send out raids (work in progress, wait a couple of updates), spies in the fortress, false identities for adventurers. Bunch of mechanics related to artifacts aimed at getting more sieges.
Latest major release is still being cleaned up, so expect several more updates over the next couple of months.
As with everything. Read the wiki. Try it out. Have Fun.
(Fun isn't guaranteed due to outside world being active. Embark near goblins. Raise population to more than 80 or provoke war through raiding).