I am interested to know ways to do partial page indexing. Specifically, I wish to exclude some part of texts in a page not be used by search engines. Is there any search engine tags in HTML pages I can use in this purpose?

Thanks.

I don't know of any tags that will accomplish that but you can put the text in a graphic if you don't want it indexed.

not sure if this works here (please tell me I am hosed if I am wrong) but you might want to try to use an iframe for the content you do not want indexed

or another option might be to use JavaScript or something like that
of course some people also cloak, but it might not be what best fits your needs

a while ago (shortly after the nofollow for blogspam stuff) Tim Mayer of Yahoo! Search was proposing some page markup tags (such as this section is navigation and this section is user contributed), but that push seems to have stalled.

I am quite surprised that there is no suitable mechanism exists despite years of search engine use! Non of the suggested techniques suitable. If they can add simple tags, writers can help search engines to pick right information for SE users. The problem is that search engines are so dumb and pick wrong pages! If they can add;

<NOINDEXING>
....
</NOINDEXING>

Will be just excellent!

What SEObook said, probably your simplest solution is to just use the JavaScript docwrite function.

I fixed with replacing words that cause misindexing with gif image text files. However things don't look natural! Currently we don't use any browser-side scripts for those who do not allow script in their browsers.

http://forums.searchenginewatch.com/showthread.php?t=4439 covers the indexing summit from our SES NY 2005 meeting, where Yahoo proposed something like this. I'm hoping we'll see it happen. Our next summit is for SES San Jose 2005.