Webmaster Forum / HTML, CSS, Scripts / HTML / October 2008

That's poor usability and poor accessibility.

It's particularly poor accessibility if you omit the ALT attribute (and
thereby use invalid markup, to add formal incorrectness to real injury), as
above and as so often.

(By the way, if I enter a page via a search engine, as people often do, or
via a "deep" link, "Back Home" looks foolish.)

It's better that you don't know that. Think about accessibility, usability,
and simplicity in navigation, and search engine friendlyness comes more or
less automatically.

"SEO" is a buzzword used largely to sell questionable services and misguided
principles. It promises "optimization", even though it should be obvious
that no optimum can ever be reached in the world of varying search engines
(which are largely intentionally varied to fight against evil forms of
"SEO").

I wouldn't be surprised if it turned out that Google traverses the href
attributes in <area> elements on saturdays only. But I would be surprised if
information about internals of Google were revealed in a manner that
justifies an assumption that the information is correct and stable.

This is an interesting question.
If you look at the text-only version of a cached page from
Google SERPs, if the page uses images maps they are
stripped out of the text-only cache (the image map links
are not in the text-only version of the cache), and
if a URL is linked to only from an image map it does not
appear in SERPs,
so it seems that links from image maps
are not seen by Google,
but if you know of an example to the contrary please write about it.

It is better anyway to use CSS for site navigation,
or for links important to you,
instead of image maps.
alistapart has a very good example of a menu that
looks like a nice image map, but is done
with CSS, not with <map>, so the links are visible to Google,
http://www.alistapart.com/d/imagemap/example2.html