I want to ask about the specific limitations of description and title tags in Yahoo or other search engines?
Okay, so whats the question? Here are basic guidelines common for all. Title is the important tag. Others might be in use, but search engines deny their use. However, I can see google showing "description" from meta in the search result page for some websites in the result. Why only some, is not known to me. Do not overdo/overstuff the tag. Keep the number of words in title to about 6-8, or better 4-5 If you add your domain to the title, add it at the end, not at the beginning, specially if it does not have your primary keywords in it. Keep the meta to about 10-15 words. A small human readable sentence. Use 5-6 keywords in the keyword tag, and try to keep them distinct. Avoid repetition. Make sure all those keywords are present on the webpage as well, within the article. And here's a tool I did that shows how a search engine might see the "spread" of your keywords on the webpage. http://www.iamrobos.com Enter a URL and enter 2-3 keywords like: mobile phone It'll show you how google sees the spread of those two keywords on the webpage. Check some of the websites that are ranking on top for the same keyword. You'll see some common patterns coming up.
Yahoo shows up to 72 Characters (Including Spaces) for a Page Title. Yahoo shows up to 161 Characters (Including Spaces) for Meta Description.
Its almost the same with Google but bear in mind to create a unique and interesting title and description within the advisable range of characters.
Yeah, I know a little bit about that, Unique title and description is very important for ranking keywords on the first page of Google or Yahoo.