The overwhelmingly high activity in the MDNA Tour thread caused the site to appear in the results of my Madonna-related Google searches. I've been lurking since.
I used a local forum and someone posted a link from ATRL and it was, I believe, a thread about Beyoncé and mediatraffic. It was in 2012, just showing how some heffas here repeat the same damn **** over and over again.
When I was following the chart run of Royals in fall 2013 (I had been a chart-watcher since late 2011), I was looking for a website where I could find live updates to the iTunes chart. I found Kworb's site, and in his FAQ I found out that he was a mod here. I came here and was instantly hooked. I couldn't believe that I had found a community of people interested in charts as much as I did. I lurked until registrations opened on New Year's Day 2014.
GagaDaily users were always talking about this site during the Applause/Roar thing about how it was like a war zone.
I had no clue about this site at all until then, I didn't even know what TRL was