What are advantages and disadvantages of using frames vs. non-frame
structure in a heavy-traffic web-site from users' standpoint.
1) Possible browser incompatibilities
2) Loading speed etc.

Hi! Thanks for the question.

I have found the following articles discussing the advantages and
disadvantages of using frames. Here are some good points and bad ones.

Advantages:

1. It is easy to change the navigation bar.
2. There is an atmosphere of consistency in your site.
3. You did not need to scroll or find the navigation bar since it is
always present.
4. It will be hard for your visitors to leave the site.
5. Advertising can always be seen in a particular frame.
6. Frames are great and much more convenient for you whenever you
always need to change content on your site.

Disadvantages:

1. Not supported by all browsers.
2. ?Some search engines cannot index framed sites.?
3. Slow loading of website.
4. ?Hard for visitors to get rid of frames.?
5. Viewing space is reduced.
6. ?Unless implemented properly, framed-pages are very hard to bookmark.?
7. ?Unless implemented properly, it is possible to design a navigation
frame which cannot be fully seen on all browsers/screen resolutions,
making full site navigation impossible for some visitors.?

?To Frame or not to Frame??
http://www.sitepoint.com/article/frame-not-frame 
 

Here are other articles discussing about the pros and cons of using frames.

?Frames: Good or Bad??
http://www.yourhtmlsource.com/frames/goodorbad.html 

?Frames -- Why and Why Not?
http://webdesign.about.com/cs/frameshelp/a/aaframesyuck.htm 

?Search Engine Optimization :: To Frame or not to Frame ?...?
http://www.perrelink.com.au/resources/seo/frames.htm 

?Some Caveats with Using Frames?
http://www.evolt.org/article/Some_Caveats_with_Using_Frames/22/293/?format=print 

?What's wrong with frames??
http://www.htmlhelp.com/design/frames/whatswrong.html 


Searched terms used:
pros cons using frames

I hope these links would help you in your research. Before rating this
answer, please ask for a clarification if you have a question or if
you would need further information.
                 
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Easterangel-ga                 
Google Answers Researcher

I would add:

1. Because frames are not supported by all browsers, particularly by
assistive technology used by blind and partially sighted people to
'view' web pages, a frames-based site might contravene Disability
Discrimination Act (or equivalent local legislation). In the UK, the
major supermarket chain www.tesco.com has developed a special
text-only accessible alternative site.

2. In frames, each individual frame is a separate page. It may
therefore be more difficult to track a visitor (maintain shopping
basket, etc) through a site if frames are used.

Owain