Free Step Dodge

Complicated answer.
The main reason I first started using her .gifs was because I noticed that she was a very expressive actress on her old show (Wizards of Waverly Place). She made a lot of different facial expressions, many of which I found funny or amusing in some way. So I started looking for gifs of her to use as "reaction images,"

and to my surprise there were a ton of them readily available that showcased a lot of her range. So I started collecting and using them.

Later as a mod, the issue came up of what to do about Double-Posting (which was a problem, but not one I felt was necessarily infraction/banworthy since there are no clear rules for the site displayed in one convenient area, and so many of the violations were accidental

- not to mention that mobile apps were glitching out and causing double-posts when they shouldn't've been). So I needed a way to discourage them by telling people not to do it. But without banning them, I couldn't merely tell them to stop over and over again because they wouldn't and it would make the site staff look ineffectual and incapable of enforcing policies.

So, rather than ban/warn everyone, I began putting the Selena gifs. It disincentived people from double-posting without serious repercussions if it happened accidentally. Furthermore, it added to culture of the site, since many people liked the running joke.