Low security space to most people in EVE, is depending on where they reside, usually one of the following things; 'irrelevant' (0.0 residents) or 'a cesspool full of griefers and pirates' (the average hisec mission runner) or even no more then 'the place we sometimes need to get our Orca through to get it to Jita' (wormhole inhabitants).
Obviously I'm painting the picture with some rather broad strokes here, but it's a fact that a lot of people in EVE know very little indeed about what lowsec is really like or what goes on there. Carebears don't because the vast majority of them just don't want to go there and ignore the area entirely. Nullsec residents often never (had/have to) spend any significant amount of time there because they either started playing EVE in 0.0 from the start or because they moved there straight from Empire skipping over lowsec all together. Wormholers tend to be somewhat isolationist having their own little community and in general care little about what happens in either lowsec or nullsec.
One the thing lowsec is definitely widely known for however is its pirates, they've been a part of lowsec pretty much from the beginning and they're a large part of what provides lowsec with, well... shall we call it colour? Let's call it colour. A career as 'a pirate' tickles the imagination of many new players.
The word pirates in the context of lowsec can have different meanings however, piracy originally means 'robbery at sea' so in the case of EVE that would then have to become 'robbery in space'. There are definitely people in lowsec who are out to commit robbery in space but a lot of the people collectively called pirates are not actually pirates by that definition.
Real pirates are a breed of lowsec inhabitants who's primary motivation is making a profit by killing and looting other players or holding them hostage for a ransom at gunpoint. To these people piracy is their EVE profession the same way other people choose the become miners, mission runners, explorers, traders or industrialists in order to earn ISK they chose to be pirates. They generally don't care who they're killing as long as it's profitable and the risk is low.
Easily the most numerous of this brand of pirates are the gate camping variety. They tend to camp high traffic entry gates from hisec into lowsec some of the systems that are famous for almost always having gate camps are Rancer, Amamake and Aunenen but there are many others.
A common method of camping gates is using fast locking strategic cruisers (most commonly Legions) for tackle in combination with Orca's and logistics ships. The way this works is that if any of the strategic cruisers get in trouble the pilot ejects from the ship and warps his pod out and the Orca subsequently scoops the tech 3 cruiser up and jumps into hisec moving the expensive ships out of harm's way. This ensures that these gate camps rarely lose ships and thus maximize the profit of killing anything that enters from hisec. Obviously these camps employ out of corp neutral scouts on the hisec side of the gate to make sure they're well clear of the gate if anything that could threaten the camp despite the precautions already taken were to show up. This form of piracy can be quite profitable. Well known pirate entities that engage in these types of activities are; the united, Heretic Army and TunDraGon.
People that hunt mission runners, explorers and ratters are another breed of 'real' pirates. These pirates instead of attempting to catch their prey at an entry point to lowsec hunt people that are already there and trying to mission, explore or even rat (yes people really do rat in lowsec). The simplest method employed by these pirates is trying to use a combination of the ship scanner and the directional scanner to pinpoint people either ratting or running scannable sites (like Forsaken Hubs etc) if they find someone they attempt to either ransom or destroy their prey for profit.
Others use combat probes or an alt with combat probes to scan down missioning or exploring ships using a combination of the direction scanner (to get a general idea of where somebody is) and combat probes. It's important the time the combat probes are out is as short as possible in order to minimize the chance of the target seeing them and being spooked.
A far more covert form of hunting is a method known as 'prescanning'. This is where a pirate scans one or multiple systems with a prober and bookmarks the sites but doesn't warp to or run them. Once done scanning these pirates start patrolling 'their' systems looking for people that do attempt to actually run the sites, once they do they try to kill or ransom them. This methodology can be very successful as a lot of explorers feel 'safe' in sites for as long as they don't see any probes out. Apparently the thought that somebody else may have already probed the site down before them doesn't occur to many people.
A lot of pirate entities have members that engage in this sort of activity amongst them The Tuskers, The Black Rebel Rifter Club and Shadow Cartel. A well known individual pirate of this type would be Kane Rizzel.
There are some other forms of piracy (like camping static DED Plexes) but the two methods described above cover the vast majority of actual pirates.
Many people end up being red flashy and are consequently labelled as pirates but their security status is just the result of the game mechanics of the arena they chose to fight in and not because they specialize in or even aim to kill people for ISK. Sure they'll loot your stuff if they hold the field after an engagement but so do people in 0.0 and those are not generally referred to as pirates either.
This lot for a wide variety of motivations decided they liked pvp better in lowsec then in 0.0 or Wormholes, some of them hate bubbles others don't like the culture and demands of large sovereignty holding entities. So instead they're in lowsec shooting other people because that's what they happen to enjoy doing.
These people can be (crudely) divided further into people that like doing small gang warfare and people that like to primarily fly solo or in really small packs of two maybe three people. People interested in small gang warfare in lowsec are essentially the same as the ones you'd find in 0.0, people looking to just shoot stuff with their EVE friends and have fun doing so. Gang compositions are obviously somewhat different due to different mechanics but the aim of the exercise is largely identical. Another noticeable difference I find is that the small gang corporations in lowsec (both pirate and in faction warfare) tend to chest-beat a lot more then in 0.0, where organizations like Hydra, Outbreak, BLOOM. and Born-2-Kill tend to just be quietly competent, lowsec corporations tend to be very loud, proud and in your face about their successes.
The final group worth mentioning are the 'soloists' they have their own unique little subculture, these people in lowsec are most commonly seen flying frigate or cruiser hulls and they get their kicks from fighting other soloists or attempting to engage gangs. Many of these people are TrueSolo™ others fly with link or combat alts to enable them to fight larger numbers. These same type of people obviously also exist (again) in 0.0 but because to population density in many parts of lowsec is much higher than in 0.0 many people prefer lowsec as fights can be found much faster. The lowsec solo community could be called little incestuous however, a lot of them hang out in the same in-game channels read and comment on each others blog's.
Some of the better known solo warriors of lowsec would include Miura Bull, Sard Caid (though his focus seems to be largely on 0.0 now) Ava Starfire, Tawa Suyo, Korg Tronix and again Kane Rizzel. Though there are many, many more.
So how do these different groups of 'pirates' generally get along you may well wonder? Well the answers is; quite poorly. And it would be weird to expect otherwise. The 'real' pirates are in it for the profit so for them taking a 'fair fight' is just a stupid thing to do, why risk it if there's no profit in it? The small gang and solo pvp'ers are looking for interesting fights and this creates a mismatch when the two distinct play styles encounter each other in the wild. In addition to that many solo pvp'ers have a need to bring their ships in through the same camped gates so there can be quite a bit of butt-hurt when their hauling alt dies in a camp. So one side accuses the other of being 'skill less gate campers' while the other side can't for the life of them even imagine why you would ever even want to engage when you don't have a clear advantage.
The Factional Warfare Connection
Most pirate entities tend to treat the various militia corporations the same as they would any other entity in lowsec. Depending on what their aim is an how they fancy their chances they will fight and/or attempt to kill them for fun or profit or both. Some militia corps could also be considered to be pirates themselves or at least engage in activities that could be categorized as 'robbery in space'.
There is however since the release of the Inferno expansion a slowly widening cultural gap between pirate entities and the militias in general. Many pirate entities tend to highly value their independence and scoff at the idea of having permanent 'blues' or 'allies'. This can and does lead to conflicts when pirate corporations use the faction warfare mechanics to acquire a state of permanent war with the opposing militia factions for reasons other than actually participating in the war. Quite often they will continue to shoot the militia members of the allied faction or even awox members of their own militia.
A large portion of the soloist pvp community has also been growing increasingly frustrated with the swarms of frigates that can now be found running the factional warfare pve compounds to farm loyalty points. The vast majority of farmers are not interested in fighting and often don't even have guns fitted to their frigates, preferring to simply speed tank the faction npcs without killing them. One soloist recently described these frigates orbiting a dot with no guns to me as; 'a whirlwind of faggotry', which quite aptly communicates the feelings of a lot of lowsec soloists about these farmers.