I saw a comment on reddit that recommended GoW and mentioned it was made by the Puzzle Quest devs. I loved Puzzle Quest so I checked it out.
So not quite word of mouth from “friends or family” (as I don’t know who this person is) and not an advert on social media either
Followed Warlords on infinite-interactive.com forums and I believe I read a link to an interview with Sirrian there and he mentioned he was working on a match 3 game called Gems of War (this was months before soft launch)
Edit: http://www.infinite-interactive.com/forum/showthread.php?393-New-Steve-Fawkner-Interview
Edit2: Yearly reminder wish for a new Warlords game 
I was playing DoTA with my friend. We lost that match and it was MMR Ranked match. We both were really down and stressed. Then my friend told me that he was going to take a break and play Gems of War. I was curious so he asked me to installed it since it’s available on steam and it’s free. So I downloaded it and start to play. Sadly my friend got new job that made him really busy. He doesn’t have time for game anymore.
I then got hooked into this game. I was like “Hey this game is so fun and relaxing!” I used to play GoW as a break from playing DoTA. Now I play DoTA as a break from GoW. Hmm that kinda remind me that I haven’t played a single DoTA game this month! 
So that’s how I got into this game. 
Me too plus when i read the description and saw it was made by the same ppl as puzzle quest(which i played 1 and 2 and the space one a little bit) i decided to try it. Also i was olaying battle island on my phone and GoW came up as a recommendation in the play store so i started and stayed pc/mobile
Article about a game studio in Melbourne on SMH online couple years back.
in android app store i looked for a:
i stayed for longer as the game turned out to have all this
PLUS it updates regularly providing new content that keep it interesting and fun
I played puzzle quest and some space one on Nintendo ds, stumbled upon game in xbox store under top free to play games.
Played all the Puzzle Quest games and enjoyed them. Was browsing Steam one day a couple years ago and came across GoW and been playing ever since! (well, with about a few months break a little while back) When I returned to the game, I saw all the improvements and was so impressed! I doubt I’ll need a break from this point on as the weekly new content always keeps me coming back.
In a similar manner to @Taisiakat I periodically search for “games like Puzzle Quest.” Found some decent games that way, like Bookworm Adventures and Gems of War. Adore the rpg elements of GoW, as I am an Elder Scrolls and Neverwinter Nights fan, and the relaxation of matching “sparkly gems.” Most of all, I liked the feeling of playing against another opponent without the usual angst of having to actually play against a stranger who may or may not be cheating, lol.
Despite the “free-to-play” label (which up to now has not interfered with gameplay enjoyment at all), I downloaded the game. I’ve stuck with the game because it remains fun, relatively undemanding of my time (no energy or “waiting” to play, timers for match completion, etc.) and provides a way to meet and chat with people from all over the world.
Saw it on Xbox store the day it came out on Xbox One, that’s what caught my attention.
Saw it when I was looking for free games on Xbox. I moved over to PC after I saw how much better the PvP system was in one of Tacet’s videos.
Saw it in the App Store and downloaded it immediately because I played all the previous versions, including the space one (name escapes me) that rarely gets mentioned. Loved them all.
Saw someone who I was playing a different game with at the time playing Gems of War. He asked if I wanted to join his guild and decided to do so.
Then addiction. 
The sad part was that it had already been out for over a year before I noticed it.
It came up in a Steam search when I was looking for a new match-3 game to play.
Lol me too
I’ve been playing for a couple years now, but I remember discovering it on Steam while looking for interesting free-to-play games. I love match-3 games, and really enjoyed the original Puzzle Quest. The card collection aspect of the game was what really caught my interest though.
I chose “it came up on the App Store”. But there was more to it than that. I’ve been a fan of the puzzle quest games for a long time. Bought the first one on psp, and played it a ton. I saw gems of war pop up on the playstation store, and gave it a try. When I realized it was by the puzzle quest team, I downloaded it on my Xbox and phone as well. I now mainly play on mobile. I was pretty upset to find out that the game had been out over a year before I learned of it. I would’ve been playing from the get go had I known about it. Anyway, thanks to the devs for an awesome game!
Found it free in the PlayStation store so I had to try it out. A very nice laid back game.
My husband used to play PQ, then moved on to Gems of War. I started playing it so we could have a game we both play, I didn’t expect to get more hooked on it than he was xD