Most of the long-time forumers seem to be saying they got into Dominion in 2011, and that's more or less the case for me; the summer of 2011 is when I really got interested in playing Dominion. But I was introduced to the game in December of 2010: my sister had bought it as a gift "for the family" for Christmas, and the four of us (me, sister, parents) played a couple games, and it seemed pretty neat. My sister quite liked it, and had played with a couple of the expansions, but for me it was more of a "well, that was fun" sort of thing.
For whatever reason, in the summer of 2011 I was intrigued (ha) by the game again. I scrounged out the box from under the family room coffee table and just kind of read through the rules some more, picking through the cards, and eventually convinced some of my friends from high school to play with me. I think there were five of us all playing base set games, having a blast, cheering on the guy who bought all the Villages (not me). By that point, I had pretty much decided that the "family" copy was now "my" copy, and I brought it back to college with me.
At college, I showed it to other people, some more interested than others. One group of people had played with it before, and I was encouraged to pick up expansions, which I did - Intrigue, then Prosperity, then Alchemy. I remember first opening up Alchemy and getting my ass kicked by the guy who picked up University (I only really saw the +2 Actions on it) and basically gained the entire Laboratory pile. Then there were the all-Prosperity games with Mountebank, Peddler, Rabble, King's Court, Worker's Village, City, Watchtower and Grand Market all shoved in together with the Colonies and Platina. It was at this point that I was realizing that there was more to most of these cards than what a cursory glance was telling me. There were more interesting interactions.
Eventually I found isotropic, and then these forums. I remember getting all excited for Hinterlands coming out, and all amped up by the previews. I got Seaside for Christmas that year, and ended up getting Hinterlands and Cornucopia eventually as well, coming back to the spring semester at college with every expansion. I remember trying to figure out where I'd put all the boxes.
Once Dark Ages came out, I had moved to a different state, and didn't really have anyone in person to play with anymore, but I still got the set anyway. I loved the game, and I loved the community of players I had found.