I noticed that alot of actresses that won the Oscar for best supporting actress, wound up fading into obscurity. The big question is, is there a curse? I can think of three off the top of my head that fell victim to this curse, Marisa Tomei, Linda Hunt and Tatum O'Neil. They win the award, and then do nothing else significant to further their careers.

As long as there are significant exceptions, there will never be a curse. There are several past winners who still had some fame afterwards:

2002 - Catherine Zeta-Jones
1998 - Judi Dench
1997 - Kim Basinger
1990 - Whoopi Goldberg
1988 - Geena Davis
1982 - Jessica Lange
1980 - Mary Steenburgen
1969 - Goldie Hawn

I noticed that alot of actresses that won the Oscar for best supporting actress, wound up fading into obscurity. The big question is, is there a curse? I can think of three off the top of my head that fell victim to this curse, Marisa Tomei, Linda Hunt and Tatum O'Neil. They win the award, and then do nothing else significant to further their careers.
Your thread reminds me of the Best New Artist grammy. There are alot of artists who we never heard from again and then there's that Milli Vanilli thing but of course we have Christina Aguilera who won and proved there is no curse. Of course, people like Madonna and the Beatles never won Best New Artist.:(

Tatum could've been a big star thanks to movies like Bad News Bears and Little Darlings after he win, but then she screwed up with drugs and getting involved with both Michael Jackson and John McEnroe

Marcia Gay Harden hasn't made very many "hit" movies since she won a few years ago.

Mira Sorvino can be added to this list too.