[aetherson]

Slippery slope is not a logical fallacy. Like any argument, it might be right or it might be wrong, and if your entire argument is, "X and Y are in some way vaguely similar, so if we allow X, then Y," then your point is certainly under-argued. But it is, in fact, the case that in at least some circumstances, people change the status quo by taking a small step outside the status quo, normalizing it as the new status quo, and then taking another small step.

If you believe that AirBnB WILL be used for prostitution, but WILL NOT be used for gambling or a drug operation, you should articulate a reason why you think there is a difference in kind that would prevent people from using AirBnB for those other purposes.

[a_bonobo]

Would this be an example for Tragedy Of The Commons?

A small group of users act rational and in self-interest (by offering prostitution, illegal gambling etc.) and therefore make it worse for the other 'legitimate' users. In the long run, the 'illegal' users destroy AirBnB (by causing stricter laws etc.) and therefore destroy their own business.

[stormbrew]

It is absolutely an informal fallacy[1]. The onus is on the person making the claim of similarity to demonstrate why that similarity is valid, so on its own it lacks any argumentative weight.

Something being an informal fallacy doesn't mean that it can't be a component of a good argument (ie. correlation not implying causation doesn't mean there are no cases where something can be demonstrated to be causitive), it means that it is not an argument in and of itself.

[1] http://en.wikipedia.org/wiki/Informal_fallacy