Google began rolling out a major update to its e-mail app Gmail Tuesday, which features a simplified design very similar to the clean look of its social network Google+, as well as threaded conversations and improved search.

Here are some of the key features within the new Gmail update.

White Space: Immediately, the first thing you'll notice about the new Gmail is the massive amount of white space. Similar to how Google updated its Docs and Docs Presentations applications, the new Gmail looks exactly like a marriage between the old Gmail and Google+, the company's burgeoning social network launched in June.

Smart Windows: When you expand or resize your browser window, Gmail will now automatically conform to the shape of the window, making it easier to view your inbox or messages in any setting.

Search: Google, which bases its entire business off search, finally adds a comprehensive search tool for its mail client. In Gmail, users can now search by the sender, the recipients, the subject, or any key words within the body of the text. In addition, users can search for messages with attachments, and search within a certain range of dates, which means no more combing through the archives for old letters.

Conversations: In the latest version of Gmail, developers wanted to make it easier for users to read back-and-forth exchanges. Similar to the way Apple made its own mail client look like iMessage conversations, Google now displays the entire exchange and users can click on individual messages to expand them. Gmail also created profile pictures, so conversations now have identical look and feel as they do within Google+.

Sidebar Customization: Some people use a lot of labels, others chat a lot, says Jason Cornwall, a user experience designer on Gmail. In the new update, users can simply click on the division between the labels and chat area and adjust it to your liking, to either show more available friends to chat with or more ways to label your e-mails.

More Themes: The last version of Gmail allowed users to add custom themes, colors and images to the background of their Gmail accounts to give them more flair. In the newest update, Google added high-resolution photos and textures, from rusty wooden planks to seascapes, so every user can read mail in style.

Display Density: The new Gmail is all about customization. If you don't like how each message looks from the inbox, you can change the display density, located in the right corner above your messages, which bunches messages closer together or spreads them farther apart from each other.

Filters: In the old Gmail, applying filters was time-consuming and overly complicated. Now, filters can be applied directly through the search box. With all of the options available in a single drop-down menu, filters can be created with minimal time and effort.

The company says the new Gmail will roll out over the next few days. Users will be able to upgrade as soon as they see a Switch to the new look link appear in the bottom-right corner of their Gmail screens.