It is a good news for Gmail users because now they can search Google docs in Gmail so they do not have to go to Google docs. Google is already very good at search but something was missing if you search about docs.
This function is possible by Google Labs so you have to enable it once to use it. To enable go to Labs, Lab is a feature of Google, you can find it in settings tab. If it is not enabled you have to enable it once, after you can enable Lab features.
Once this feature is enabled you will be able to search mail and docs.
