Eazygoin - 12:14 pm on Dec 17, 2005 (gmt 0)
Not wanting to contradict anyone, but merely passing a comment from experience, 100% of my titls and description tags were changed, back in June, and there was NO adverse effect on the site.
Since then, I have continued to tweak both for the homepage, so as to ensure the tags provide absolute clarification of what my main site is about, again with no adverse effect.
My main keyword has been at number one for a search of 22 million+ since June, and remains there. Conjugations of the main keyphrase also remain in top positions.
I cannot see Google penalising anyone for trying to improve their site, BUT if they are trying to spam the system then thats another story!
What I do notice is an aweful lot of websites misuse the title tag, but as long as it is clear and concise, and relates to the content, then IMO it should be fine.
As someone said yesterday, NOBODY knows how Google works when it comes to these things, so we can only speculate, without giving clear cut statements on what is right or not.