Please read the consequences.
As frequently happens on the wild frontier, ethics often takes a back seat to profitability. This certainly explains why the corporations will buy the biodata of planets you have inflicted genocide on "because the natives looked restless."
The major corporations are not above committing their own atrocities, though. Each major corporation has at least one operation going on that they'd rather nobody found out about. These operations happen on worlds covered in security troops, who usually tell you things like "you shouldn't be here." Security troops are much like alien lifeforms---sooner or later, they're likely to become hostile. For bonus points, the building on a blackmail world usually has some alarms scattered throughout it, which will make everyone (or maybe just everyone near the alarm?) hostile to you.
Each blackmail world has a multiple-level building on it. Somewhere on the bottom floor of the building, there will be a computer that has all of the sordid details of whatever the corporation is trying to accomplish. If the research involves slave laborers and/or research subjects, there will be some hapless victims wandering around, usually on the second floor or lower (with a level full of security guards above them). These victims will complain about work conditions, being enslaved, having alien symbiotes shoved down their throats, etc., but will never participate in an uprising against the security troops. They will become angry and hostile if you slaughter security troops near them, in fact.
If you are very lucky, a single blackmail world will have two pieces of incriminating information on computers on adjacent floors, that implicate different corporations.
Once you have escaped a blackmail world with some juicy information, you have two options: blackmail the corporation that committed the deed (for 1000 credits every time you dock at that corporation's station and visit the office), or sell the information to any rival corporation for 10,000 credits. If you sell the information, then the evil corporation will be outed, and its stock will fall through the floor and it will be forced to close down operations on the frontier. For each station they held, a random, different corporation will take it over.
Option 1:You may decide to turn in a piece of blackmail evidence to a different company for the 10,000 credits, if so, the company whose had their secret exposed will disappear and their stations will be taken over by rival companies. This means that you may no longer turn in or recieve any quests from them.
Option 2:You may also decide to blackmail a corporation for 1,000 credits every time you dock or you may spam it at the station interface BUT doing so will cause an immediate drop in relationship between the corporations and you. The drop is significant and after leaving the station all corporations and stations may be hostile to you. You will have to kill pirates to raise the level high enough to be accepted back into the stations. This will also kill your bonuses. Being at war with corporations means you are at war with EVERY npc, every crew will treat you as a pirate and even minor stations civilians will attack you. This does not affect your relationship with the pirates or neutrals in any way.
Eridiani Explorations is manufacturing highly-addictive, hallucinogenic drugs (The planet will have a hallucinogenic atmosphere)
SHI is using slave labor
Omega Bioengineering is creating half-crystal half-human hybrids
Triax Traders are secretly funding the pirates.
Note:There is a suspicion that the atrocities are committed by randomized corporations. (so bioscience isn't only done by Omega Bioengineering)