Wifi stands for "wireless fidelity" and refers to certain kinds of wireless local area networks, or WLAN (as opposed to LAN, or computers that are networked together with wires).
Any device you have with a wireless card (most likely your laptop, phone, tablet, and e-reader) can connect to the internet via wifi. And what's a wireless card? It's basically like a modem but without a phone line. What's the difference between wifi and the internet? The wifi is the wireless network you connect to that allows you to access the internet.
As a traveler, knowing where you can find wifi is key, because getting online makes the travel experience so much easier. When you can get onto the internet, you'll be able to book a hostel, find directions, buy a flight ticket, catch up with friends, and share your photos to social media.
How to Find Wifi Hotspots
Wifi hotspots are places where you can find wifi, free or paid. Airports are likely wifi hotspots, and many train stations, hotels, cafes, and bars have wifi hotspots. Internet cafes are rare, so don't rely on using those as you travel.
You can log on to free wifi at hotspots where wifi is intentionally offered to the public without charge; some wifi networks are protected with passwords and you must pay or otherwise be given access to log on. Generally, you can log on to paid wifi with a credit card online; your screen may open with a splash page for the wifi provider, offering you payment choices, if you are trying to log on to the internet in a paid wifi hotspot.
One useful tip for when you're traveling is to download Foursquare. Many of the reviews and comments on different restaurants, cafes, and bars share the wifi password, which makes getting online much less of a hassle.
How Common is Free Wifi When You Travel?
It definitely depends on the country you're traveling in, and, funnily enough, on whether you're traveling on a budget or not.
I've always found it rather strange that it's far easier to find a free wifi connection in a hostel than in a luxury hotel. If you're a luxury traveler, then, you'll want to make sure you set aside some of your budget for getting online, or resign yourself to heading to a McDonald's or Starbucks every so often to take advantage of their free wifi.
If you travel on a budget and stay in hostels, you'll find that the vast majority of them have free wifi and that speeds are increasing every year, so connections will rarely be unusable.
Any exceptions? Oceania is one region of the world where wifi is slow and expensive. It's rare to find free wifi in hostels in Australia, New Zealand, and elsewhere in the South Pacific. I even found a hostel in Australia that charged $18 per six hours of wifi!
Should You Travel with a Laptop?
There are advantages and disadvantages to bringing your laptop with you when you travel, but for the most part, I do recommend doing so. Booking flights, reading accommodation reviews, catching up on emails, watching movies, storing your photos... they're all so much easier on a laptop rather than a phone or a tablet.
And yes, you can say that traveling with a laptop ruins the travel experience. That travelers spend their downtime in hostels staring at a screen instead of making conversation. But that's not going to change whether you travel with your laptop or not. And trust me, 90% of the travelers you'll meet in hostels are traveling with a laptop, and there's a good reason for that. It's convenient, it doesn't have to be super-heavy, and it makes doing things online so much quicker and easier.