I've said in this forum that the two things that have turned my head into mush the most are cell phones/providers/plans and vaping, and not necessarily in that order.
Fortunately, vaping isn't all that hard to figure out once you get past all the lingo. I could write a small book here, but I'm going to try keep it short and simple.
If you, or anyone reading this already knows any of the following, my apologies.
First, there's a movement underfoot to refer to E-cigarettes as "PV"s, or "personal vaporizers", to downplay the connection to cigarettes.
All PV's work by using a [battery] to heat up a coil or coils in an [atomizer] that in turn heat up the [e-liquid/e-juice/juice] that is made of [propylene glycol (PG), vegetable glycerin (VG), or a combination of both (commonly 80% PG, 20% VG). The juice actually being vaped typically contains anywhere from 0 mg/ml (milligrams per milliliter) of nicotine (that's what I vaped for the first six months) to 36 mg/ml. with the most typical maybe being between 12-24. PG makes for better [throat hit] (the feeling you'd get from a regular [analog] cigarette, and VG produces more vapor, less throat hit. (It's been said that it's not that the PG itself produces throat hit, but that it just lets the nicotine do its "throat hit thing" better) Hence, the common use of a blend of PG and VG in juice.
To demystify the "mg/ml" nicotine concentrations: the metric system is a beautiful thing. Evidence: 1,000 ml = 1,000 mg. Pretty sweet. So, a nicotine concentration of 1,000 mg/ml would be 100% nictotine molecules, and two drops would probably put you in the morgue. Most juice vendors sell flavored juice in a maximum concentration of 48 mg/ml; and for the record, the "ml" part is almost always omitted, and the juice is just referred to as "48 mg", 36 mg", and so on. [DIY] is the mixing of your own PG, VG, or PG/VG base, flavorings, sweeteners, other additives ((like [WTA], (whole tobacco alkaloids), just forget about that for now), and of course, nicotine. Nicotine is commonly available in concentrations up to 100 mg. Again, the higher the concentration, the more critical it is that you keep from ingesting it or getting it on your skin.
As for gear:
PV's run the gamut from small units that look like and are about the same size as cigarettes to more and more exotic [mods] (modified PV's, essentially) with advanced features like huge (usually removable) batteries, variable voltage, variable wattage, very distinctive styling and shapes, and even storage for bottles of juice.
Many vapers try to discourage people from getting PV's that look like cigarettes (like the crap you see in gas stations, or heavily advertised), and I'm one of them. They just don't perform as well as other very nice alternatives that fall between the two extremes noted above. The most common of these alternatives, and probably the most advised to new users, are based on a standard that I think was introduced by a company called Joyetech, and that is the "510" standard. The distinguishing feature of this standard is the thread size, both internal and external, on the "business end" of the battery. I think it's safe to say that there are more optional types of vaping systems that use this standard than any other. Some of these include [cartomizers] ((a combination of a [cartridge] (the single crappiest way to try to get juice to flow into an atomizer) plus an atomizer, atomizers with [tanks] that hold 1 ml of juice or more, stand-alone atomizers used for [dripping] (just like it sounds - you drip juice right onto the coils of an atomizer and inhale the vapor using a [drip tip], usually for the purpose of trying a new flavor of juice without filling up a whole tank, or cartomizer, or (god forbid) a cartridge, or [clearomizers], newer devices that hold even more liquid than an eGo-T-type tank and seem to deliver the juice to the atomizer coils exceptionally well.
(A little clarification; I slam cartridges because the worst PV system I've ever experienced used a separate atomizer and a separate cartridge (a cartridge just being a little plastic tube filled with some kind of absorbent material that was somehow supposed to magically deliver the juice to the atomizer coils, a feat I have never personally witnessed). Next best (IMO) and vastly superior is the cartomizer, which combines the two into one, with the coil(s) of the atomizer nicely nestled among the absorbent fibers so that the juice can actually make contact with them and become vaporized, which is really pretty much what we're after).
A note on "Joye", "510", and a new term, "eGO"/"Ego"/EGo":
Think of "Joye" or "Joyetech" as "IBM", and all references to "510" or "Ego" (and all its variant spellings) as "IBM-type PC's", as opposed to Apples, or any other type. Just as all IBM computers run the same basic programs, all "510" stuff will interchange, whether it's made by Joyetech or not.
The 510 battery is similar in size, but maybe slightly more powerful, than those found in other (approximately) cigarette-sized PV's, the most common of which I think are generally referred to as belonging to the "808" class of devices. The Ego batteries are bigger still, and Joyetech also makes one that appears to be about the size of a half a stick of dynamite.
Batteries are rated in milliamp-hours [mah], with the 808-type being in the low hundreds, the 510's being around maybe 280-400, and the eGo batteries generally running between 650 - 1100 mah. (I use the 1000's). The huge one that Joyetech makes is I think around 2,850 mah. As I mentioned earlier, "mods" (you'll hear about the Prodigy V 3.1, Darwin, Provari, Reo Grand, and many, many more) almost always use replaceable BIG batteries (I think the Darwin is about the only exception - it uses a BIG non-replaceable battery), with names like 18490, 18500, and 18650.
Final note on batteries: I think that 99% of the experienced vapers on this site would tell you not to bother with an [automatic battery] - one that detects when you take a drag and turn the battery on, well, automatically. They tend to get crapped up with juice and stop working, and don't give you as much control over your hit as a manual battery. Automatics seem to be geared mainly toward your 90-year-old Aunt who couldn't find the front door, much less a little button on a PV.
Voltage is a big deal in the vaping world. Most 510 and eGo batteries are around 3.7 volts, and the variable voltage mods might run anywhere between 3-ish to 6-ish. You'll hear a lot about the [resistance] (in ohms) of atomizers. The voltage of the battery and the resistance of the atomizer have to work well together to give you plenty of vapor, yet not damage the atomizer. The vast majority of vapers, myself included, will say that a [low-res] (low-resistance, like 1.5-1.7 ohms) atomizer(/cartomizer/clearomizer) works best with the (relatively low) voltage of a 510 or eGo battery. Variable voltage [VV] gives you much more control over your vaping experience; the ability to fine-tune the interaction of a wide variety of atomizers and the battery power of the device. Other factors probably come into play as well, like the PG/VG mixture, ingredients in the juice, or whether it's a cold day out.
That comes at a price though; a Provari VV is about $160, whereas you can get my recommendation for those just starting out, the Joyetech Ego-C , for around $85, which will buy you a starter kit containing TWO complete PV's plus 3 extra atomizer [heads].
The Joyetech eGo-C is an improvement on the Joyetech eGo-T, which was an improvement on the Joyetech eGo.
The eGo system, I think, used separate cartridges and atomizers, though most people might have used cartomizers with it. The eGo-T ("T" for tank) uses a tank to hold about 1 ml of juice that it delivers pretty nicely to the atomizer. It's what I use for now, but not for long. The next generation of eGo, and what I'm shifting to, is the eGo-C (the "C' is for "changeable"). The difference between the -T and the -C is that the -C splits up the atomizer section into three parts, making it easier and cheaper to maintain or replace just the working part of the atomizer section which they call the "head", which is essentially composed of the heating coils. The atomizer coils of any PV do need cleaning periodically, like maybe once a week, and with -C heads costing about $5 each, that makes for cheap maintenance. And with a complete setup going for about $42.50 (starter kit price divided by two), it's a good, cost-effective way to get into a system that's dependable, performs well, is easy to maintain, can take almost any accessory under the sun, and will let you vape as many different flavors as you can buy setups to load them into.
As LadyPixel (Above) said: "you need to actually become familiarized with the many, many different methods of juice dispensing (atomizers with dripping/atomizers with cartridges/cartomizers/clearomizers/tankomizers/tanks/carto-tanks)" - and I can't think of much that will allow you to do that better than the 510-style 1000 mah Ego-C tank system.
Juice:
I can't say enough good things about Tasty Vapors. Great flavors, great service, good prices, and one thing that I haven't seen anywhere else: what they call "Doublers"; 2- or 4-ounce bottles of zero-nic flavored juice so you can cut the nicotine strength of any of their flavors with out diluting the flavor. Since the cost of the nicotine juice per ounce is the same whether you get 12, 24, 36, or 48 mg strength, I just get the 48 mg and reduce it to whatever nicotine level I want with the much cheaper Doubler liquid. So far I've tried Atomic Cinnacide (Atomic Fireball - very good but too sweet even for me to vape steadily), Geoff's Blend (very good), and Kretek (clove cigarette flavored - amazing).
Other vendors that I keep hearing people recommend are Backwoods, V4L, Blumist, Gourmetvapor, VaporTalk, Alien Vision, Vapor Shop, EC Blend, Tasty Vapor, and Copper Creek.
Happy vaping.
And to the veterans here who know a hell of a lot more about this than I do; I probably got a few things wrong, so please be gentle. Down deep, I'm really quite a delicate little flower. TIA
***
I've had a revelation about 510-compatible PV's with replaceable 18650 lithium-ion batteries, like the e-power. 2800 mah, you can replace just the battery when it craps out, you can have a bunch of them in a charger so you don't have to tie up your PV, and you can replace just the switch if it breaks. Since they're 510-threaded, you can obviously use any type of system with them. Speaking of which, look at the Mom and Pop Submarine tanks. They slip over a cartomizer with a hole/holes/slot/slots in them, and appear to kick ....
I still like the eGo batteries for the coolness of the circuitry; press 5 times to lock "off", 5 more times to unlock, and the newer ones change colors to let you know the power is running down. The (genuine) Joyetech (/Ovale) eGo-C starter kit is still a solid way to start out (IMO), just for the quality of the design, features, and just to see what eGo batteries are like. Looks really streamlined as well. You can always move on from there, and not feel like you've wasted any money. Good learning experience.