Via Giant Bomb*
In the first game, Gianna recruits Shepard to retrieve information about Administrator Anoleis (which you can choose to do or not), and in the second, you can help her (again, or not) convince an asari to show you some prototype mods that she stole back on Noveria. You learn quite a bit about her: she grew up poor but was surrounded by wealthy kids, so she figured out how to fit in with them without revealing her own background. She wanted to be a cop but wanted to help her family with bills, so she went with what would pay those, hinting at a much more tender version of herself that she doesn't present to just anyone. Oh, and she also hates skirts.
Sadly, Parasini doesn't return in ME3, which I found disappointing. It wasn't like corporations stopped being greedy just because there was a war on. I mean, in the second game, there was a volus on Illium that was "short-selling prefabs" for monetary benefit, even though he was profiting from the misery and paranoia of the human colonists that wondered if their colony was next. Hell, she could have even been a contact for Shepard, finding information that hinted at Udina being dirty, therefore setting up the Cerberus takeover of the Citadel a bit better**. Plus, Shepard had plenty of side missions that had absolutely nothing to do with the Reaper War, so it wouldn't have detracted from the story, and we'd have had the chance to see her one last time. Damn, even Emily Wong sent an email, but from Gianna? Nothing. It was like she just disappeared.
Honestly, I just loved interacting with her. There was obviously some sort of unresolved sexual tension there, regardless of Shep's gender, but for the most part, she kept it friendly and professional. Both Parasini and Shepard were fighters, albeit a different type, and there was a mutual respect present that could have made for a very interesting relationship, romantic or otherwise. I kind of hope that Dark Horse does a series based on Gianna. While I haven't really enjoyed everything they've put out in their Foundation series, I would think that someone would jump at being able to do a Corporations Are Evil Featuring Gianna Parasini story. I know I would. Hey, Dark Horse! HIT. ME. UP.
* In case you can't read it, the text says, "I love nailing asari. So ageless and superior - then you get them, and they squeal like schoolgirls."
** This was a problem that I had with the game. There wasn't ever really an explanation as to why Udina helped the Illusive Man (not that anybody cared because Udina was pretty much universally despised), and it was just kind of sprung on you.