Will the global search function be further improved by providing results with the keywords found? Just like the search results in Yahoo! or Google.

When I search some keywords, the results shown not only provide the title of the topic, but also the content of the topic (just several sentences) that matches the keywords.

At this moment, when I enter a keyword for search, the results shown are their topics. It's actually time-consuming to find the possible relevant information in that topics.

My second suggestion is that users should be allowed to choose which sections to search for, may be single section, multiple sections, or even all sections. I mean achieving this need not to reload the page, but just like the fast reply in this forum.

And this. What do you think?

This question has come up before a few times. Somewhere in the vaults of theis forum/ news archives there is a feature where someone introduced a search function that returned a context snippet similar to google etc.

The second part of your question is already there, as I read it. I mean you have tick options in the advanced search page to select wich part/ or which module to search in.

Another option here: use the xoogle module. Assuming you site/s have been crawled by google, the module will search googles cache for just entries of your site and return context results within the module page. Also gives options for regular site search as usual.