What are wormholes?:
At certain locations in a star system, the potential for forming a wormhole and folding space is greatest. Stargates use these special areas in space to connect star systems together permanently with unseen wormholes. Starting with an unidentified cataclysmic event that caused the destruction of a planet in 3HQC-6 in Outer Ring and the far-off planet of Seyllin I, new naturally occurring but temporary wormholes are beginning to open randomly throughout the star systems of New Eden. The big exploration factor comes in the form of 2500 nearby star systems that the EVE stargate network doesn't reach but which the new wormholes do. These are completely new solar systems that have never been charted and were once inhabited by the ancient races.
All of the new systems have a security rating of 0.0 as police ships have never ventured there. This means that if you're in one of the 2500 new systems, pirates can potentially enter and hunt you down. Since it's 0.0, specialised PvP tools like mobile anchorable warp disruptors, bombs and interdiction spheres also work. Most importantly, wormholes into these unknown systems can actually spawn in high and low security space. Although there's a warning before entering about the lack of CONCORD presence before you jump through a wormhole in high security space, the rewards in these systems are high enough to tempt a lot of pilots to risk entry.
While some pirate corps are content with camping stargates, the more organised and adventurous ones have recognised the potential of wormholes and begun invading the unknown systems to hunt for targets. And since these wormholes have mass limits, this is mostly a boost to small gangs and recon ship squads as massive fleets won't be able to enter. Within hours of entering a wormhole in the Black Rise region, our crew had a run-in with Veto pilots in recon ships. Using combat probes, they were able to very quickly scan down our very expensive Orca and landed just 70km from it. Thankfully, the Orca was cloaked the entire time and survived the ordeal. The pirates eventually left the system when we managed to make the wormhole go critical and threatened to trap them inside.
Low security space (lowsec) has long since been considered worthless by most players. The lack of anything valuable enough to offset the risk of piracy has made most areas of lowsec into ghost towns. In the early years of EVE, mining in these areas was over twice as profitable as mining in high security systems and the risk of piracy was lower as the playerbase was much smaller. Nowadays, the ores restricted to lowsec are worth less than veldspar and the risk of piracy is much greater.
When exploration was released, the more profitable exploration content in lowsec compared to that found in high security space helped to improve the profitability of the areas. Bonuses to mission rewards from agents have also helped, but not significantly. With the advent of the Apocrypha patch, not only does lowsec now sometimes get battleship sized NPCs in asteroid belts but the area also tends to link to more profitable wormhole systems. Class 3 wormhole systems have a strong tendency to link to low security rating systems and the anomalies there can produce upward of 120 million isk per hour for a group of four pilots. If that doesn't tempt you go to into lowsec, I don't know what will.