An investor is heavily influenced by the successes and failures of past deals. There might be no scientific evidence that "you can't make money in healthcare diagnostics", "ad tech is dead", "companies founded in Italy are hard to scale", "that sounds like IT management, and that is a feature rather than a market" but the investor, with sample size n=1, is a true believer.
In the first few seconds of an interaction with an investor, they will try to put you in a box of something they understand and/or have invested in in the past. Help them do it, and say that you will clarify later why "mobile social network" is not exactly what you are doing.
If the dialogue with the investor continues, pay careful attention to of the cough comments about past experiences where she burnt her fingers on something that sounds similar. These reservations go really deep, an investor won't trip over the same stone twice. Understand the concern, and really explain why your situation is different. If you don't know the answer right away, get back to her later after you have collected the facts.