When a frame is used, one parent page is created and all subsequent pages are loaded within the frame-work of that page. If you've been to our site promotion page, you understand the importance of meta tag keywords and descriptions. Since frames nestle all pages within a parent page, much of this effort of creating keywords for each page has been negated by the frame because the only page being looked at is the main frame page. That's a significant penalty to pay for a scroll bar which also uses up valuable screen space, clutters the page and creates some confusion. The pitfalls of using frames is discussed in greater detail on the site promotion page.
Frames are also difficult to set up properly.
If not configured correctly, multiple frames may be displayed on the same page. If a visitor enters the site through one of the sub-pages, the frame of the parent page won't be displayed. You may either end up with no frame or multiple frames on the same page. One of the few times a frame could be used is when the web site is one fantastically large page and there are multiple links throughout this page. This is, however, an extremely weak design method and should be avoided.