JesuOtaku! I started watching her videos after watching her "Top 15 Stupidest Izzyisms". I'm still waiting for the rest of her Digimon Retrospective, but I guess that sort of thing takes a lot of work, and she doesn't have nearly as many fans to bother her as, say... Doug. Or Linkara. Or Spoony. Or any of the actually popular contributors.
Actually looking back at that video, (I'm assuming you mean her cameo in Prof's and not her review which came out a long time ago) it looks like she still does have her hair died, the lightning makes it hard to tell
She is Hope Chapman, aka JesuOtaku, an anime reviewer for Anime News Network, the Desu Des Brigade and TGWTG.com. Her expertise lies in licensed anime with strong emphasis on the dubbed version of the show while still analyzing every aspect of the release. The reason I enjoy her videos so much is because rather than just saying "this sucks" or "I like this" so goes checks every element of the series, from story to character development to animation and how the dub fares from the original Japanese. She often implements humor in the form of silly sketches at the beginning and end of the review as well as red snark titles sprinkled throughout the video. But her review talents are great and I admit that because of both her and MarzGurl I've gotten back into anime after a long hiatus.
Hope this helps! (JesuOtaku, feel free to correct me if I am wrong in anything)