I've met quite a few over the years, but just this past trip to WDW (last week and the week before) I met 3.
One was planned because she and I have been buddies online for many years. Back in 2001, when I met Dan Murphy the first time, he called her so she and I could talk, but I only got to leave a message. So when we discovered we were both going to be in WDW at the same time, we jumped at the chance to meet. And it was awesome! Spent hours together, but still not nearly enough time!
One was another long-time DISer who lives in FL, and planned to go to F&W at some point with her DH, and as it turned out, they did, and we were able to meet up. Delighted to meet them both, but wish we had had more time...DH and I had tickets for MNNSHP and had to get going. Next time, lunch, so she and my DH can talk recipes and cooking.
And the third was another long-time DISer, and while I was at an Eat to the Beat Concert, I looked on FB and he had posted that he was at the same concert. So I replied that I was there, he said where he was sitting, which was on the opposite side from me, and then my phone died. After the concert, DH and I walked over to that side, and I couldn't believe it, but I recognized this DISer, altho I don't think I've seen pictures in a long time. Had a great chat with him too!