Rogue's mutant powers consist of absorbing the mind and powers of the being she touches, if the contact is produced skin to skin. She usually wears clothes that cover her whole body, so she has to take off a glove -- or other piece of protective clothing -- to make the contact. She prefers a kiss to get her power working. She has proven able to absorb alien beings as well as non-mutants and mutants.
Another important thing about her powers is the longer the contact with the victim, longer the victim's psyche remains in her. A curious plot happened when she absorbed Colossus' powers while he was deadly injured. She also absorbed those injuries, not only Colossus' power and mind.
Rogue prefers not to use her powers, but does use the ones she "borrowed" from Ms. Marvel. She discovered her mutant abilities the hard way, when Cody, her boyfriend, went catatonic after kissing her. Then, she was forced by her father to leave home. She was later recruited by Mystique, who wanted her for The Evil Mutants Brotherhood. Although Mystique just wanted her as a pawn, she always treated her like a mother should treat her daughter. Mystique even chose to let her leave and join the X-Men after she absorbed the powers and mind of Ms. Marvel rather than see her suffer.
During a fight Ms. Marvel accidentally maintained contact too long with Rogue. The absolute absorption of her mind and a permanent acquirement of her super abilities was the result. A battle was taking place in her mind, and she asked for help from Charles Xavier. Ever since then, she has been on the good guys' side with the X-Men.
Rogue also has invulnerability, super strength and flying, stolen from Ms. Marvel. She can't control her power, so she is virtually untouchable. The only time she seemed to be free from that is when she was jailed in Genosha, during the mutants' first visit to the island. Since the experience of being helpless to the magistrates was pretty shocking, she let her Ms. Marvel back in control. For a while, both sides of her mind fought for that control of the body, turning her eyes from green to blue when Ms. Marvel was there, but she finally got free of it (although she still has the powers) with the psychic help of Jean Gray. Although she is now free of Ms. Marvel, she has absorbed the memory of Belladonna (Gambit's wife), so once again her brain is troubled with a second entity struggling for control of the body.
Here is a list of Rogue's absorptions(sorry, not yet in order):
Cody (the very first one), Belladonna, Gambit, Ms Marvel, The Human Torch, Alien Phantoms from ROM, Wonder Man(whom she COULDN'T absorb), Mefisto(whom she didn't manage to absorb), Loki (whom she failed to absorb during AF&The X Men), Archangel, Colossus(in a liquid nitrogen shell), Nightcrawler, Storm (the first one to be willingly absorbed), Longshot, and Wolverine.
Rogue is Magneto's wife and the leader of one division of the X-Men. Although her mutant ability affects anyone she comes into skin contact with, her magnetic powers along with Magneto's is able to create a magnetic buffer that allows her to touch Magnus without absorbing his personality. Perhaps realizing how precious life is after the Scarlet Witch gave up her life to save Rogue's, Rogue has become as devoted to the dream as Magneto. Apparently, she is also as idealistic as he, for when Sunfire reports a culling, she takes her band of X-Men to Chicago in a futile attempt to stop Holocaust and his army of Infinites.