Both recently made acquisitions that should serve them well in the long run.There are all sorts of short-lived trends that make some companies money but turn out to be fads that aren't worth investors' hard-earned money, at least not those with a long-term mindset. Corporations that can deliver strong returns over the long run tend to be leaders in industries that won't decline in prominence or disappear anytime soon. That describes Fiverr (FVRR 1.12%) and Airbnb (ABNB 0.38%) well. Though these two stocks h ...