Hi Soren, long long long time no see or hear for that matter!
Where have you been?
Yep, has been a big no no for a long time frames, about 3 years ago I took over a website for an agent to promote and his site was built in frames.
When you looked in the search engines trying to do some research on his website, the site did come up (on the 18th page!) but without the side navigation, the header, the footer....
He doesn't use my services anymore (personal reasons, you would understand if I told you!) and he has gone back to his old web designer this year, and guess what? The lovely frames are back, he has lost all of his high SERP's and his online business has more or less disappeared from the face of the earth!
Here is a good example of how
frames can destroy your online business. See if you can get to any other page from this!