It is impossible
to bookmark (Firefox) or make a favourite (Explorer) of
an individual page contained within a frameset. Only the enclosing frameset itself can
be bookmarked, so any enclosed pages had better be easy to find! (a cunning solution to this problem is to make a separate frameset for every page that can be bookmarked. It is a lot more work and compromises your ability to replace an ad banner or set of navigation links by simply setting a new link from a central frameset, which is often the whole point).
Printing is sometimes only
possible of individual pages and not the whole frameset, so navigation elements
and logotypes may be omitted when your customer prints a content page.
Frames divide up
the screen into even smaller boxes. Removing the frame borders and keeping the
contents concise so that scrollbars are not needed will reduce the damage. Keep
in mind the wide range of sizes that potential viewers may use to view the site
- the screen of a smartphone can be quickly consumed by the left hand navigation frame leaving
little room for designed content.
Some old browsers (dinosaurs before Explorer 3) may not display frames properly.
Frames are more difficult for search engines to index and so may reduce your ranking in search results.
Framesets are unlikely to instill confidence for an e-commerce site.
Frames are tricky to master and invite trouble for the web designer. You need to remember to target your links so that pages open in the correct frame.
Web Design Group: What's wrong with frames?
Useability expert Jakob Nielsen's Alertbox for December 1996: Why Frames Suck (Most of the Time)