hell no, it would definitely hurt your app.
It will only hurt your app if you don't know how to properly phrase it. In interviews, resumes, etc. you can only express things with a few words. As such, you face a dilemma that is easily solvable. The dilemma is that much of the activities we do on RuneScape will sound like money laundering, being a bookie, etc. to those not familiar with the game. (Yes, some players performed these illicit activities, but not all of us...) There are two solutions to this. One is providing a lengthy explanation of what you actually did and how it is completely legal and respectable. The other is simply using ambiguity to your advantage (this is something everyone needs to learn how to do for interviews and resumes).
Consider this. Instead of saying "I was a host in Dragon Dyce that handled over $100,000 in bets", you could say something like, "Facilitated the development of trust based markets by providing escrow services for over $100,000 of player assets". This is a completely true statement. It also piques the attention of the employer. Given a chance later on, you can talk about your experiences in more detail with your employer if he/she is interested. (And from my experience, they usually are.)
So yes, include it. But be smart about how you include it. I've been OFFERED internships at places like Goldman Sachs by people who learned about my activities on this game. The amount of money that has gone through children's hands as a result of gambling/merching/etc. on RuneScape over the past few years is truly astounding, and this is something that many many people find interesting. Those of us who were intimately involved in this movement can and should use it to their advantage when pursuing real life careers.