Twix doesn't need much advertising anyway - they're delicious. But having Abigail Spencer as a spokeswoman certainly doesn't hurt.
Recently, it seems like there is a fringe group of remarkably hot actresses who feel the need to peddle stuff in commercials. While the Palm Pre girl I saw the other week probably only appeals to certain types, women like Kate Walsh (Grey's Anatomy and some car commercials) and Jill Wagner (the Mercury girl) have enhanced their status with their commercials.
With that in mind, meet Abigail Spencer, also known as the ridiculously hot girl from the Twix commercials. The odd thing is, as I allude to in the opening paragraph, her credits are a bit better than you would normally associate with some random hot girl in a commercial for a candy bar. She has played characters on plenty of decent shows - CSI, How I Met Your Mother, Mad Men, My Boys, Gilmore Girls, All My Children - and she even comes off as likable in the Twix commercial.
This, combined with her unbelievable hotness, is probably why they commissioned a SECOND commercial with her, and also feature her in an Internet web series. The only other one I can think of who earned that honor is Wagner, and the Yellow Book hot girl, and by "honor", I mean that they aren't really considered a big-name get for a commercial yet they've been in multiple ones. Oddly, she's 28, which is a bit older than you'd normally associate with a commercial hot girl. However, I think this only adds to her appeal.
On a side note, the guy in that commercial with her, and the guys in all of the Twix commercials, are complete douches. I'm not even going to bother looking up what his name is, because that is how much I dislike his character. Dear Twix, get rid of the douche-y guy who is talking to her about blogging, and just have Abigail Spencer talk about how awesome Twix are. There, I just made you $50 million.