Can I trust the Internet?
Well that's a loaded question. I would answer, "maybe?"
It's easy to let seemingly insignificant details fade into the background of our Internet-connected lives. But those pesky details determine whether your holiday gifts arrive safely, or if you've just given a nice holiday "bonus" to some scam artist anywhere in the world.
At a high level, the Internet, just like anything else, is essentially a Client (you) / Service (them) model. Clients request content from a Service provider which can be anything or anyone. All Client/Service models require some level of Trust. You trust your bank to keep you money safe, rather than store it under your mattress (hopefully).
Everything we do as humans revolves around trust, and the Internet is no different. We trust ourselves because we can see and feel our own experiences. We know what our own experiences teach us because we experienced them first-hand. We often trust those closest to us, because we have established histories with them. Trust in this case is often around protecting our fundamental human needs. Needs that range from food, water, and shelter, to possible financial support at times. Familial trust often starts a birth (or other young age) and is built over time. Friendships bring a second source of trust, but also take time to build. The same concepts apply in the virtual world. The longer we maintain an account with an online service provider, we grow more comfortable with using the service.
Just keep an eye on who or what provider which services you use. And be aware of what their expectations are in return. Just remember, all web services cost money to maintain. Ask yourself, what's the provider getting from me if not a membership fee?