Maintaining a page linking to such frames sites, each with their own set of instructions, each structured differently, and each using its own vocabulary, is difficult and time consuming. I recently attended a webmaster's conference in which this topic came up repeatedly. Large organizations are facing a common problem - even with nice, well organized corporate home pages, Web sites within the organization tend to adopt practices that defeat efforts to build an interconnected, coherent web of information. So a network that is twice as large will be four times as valuable because there are four times as many things that can be done due to the larger number of interconnections. Conversely, a network of information that is subdivided into disconnectd units is less useful.
Interconnected information is very useful.
Its much easier to link to relevant information rather than having to gather, organize, and present it yourself. In the same way, others will want to be able to link to information within your site. Frames makes such interconnections more difficult. Accessibility A frames layout is inherently problematic for someone using a braille or audio browser. The frames design shows multiple page views simultaneously, no problem for a person viewing the page, while audio and braille browsers read a page linearly, one word at a time.