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If you access Gmail via a phone or email client using POP, you may be frustrated by the fact that any action you take, such as reading, sorting or deleting, doesn't sync with your Gmail account. You may have read and sorted all your new mail on your phone, for example, but when you log back in to Gmail using a browser, you're presented with a full inbox of unread messages that you have to re-read and re-organize. What you may not realize is that you have another option that solves these problems: IMAP.

It can be a little confusing to learn about different ways to get email on your phone or in an email client such as Thunderbird or Outlook, but this breakdown of the key differences between POP and IMAP should help you decide which way to go.

There are two ways your devices and clients can communicate with Gmail:

1. A one-way communication path (POP). Your device asks us for data and pulls it from our servers -- but that's it. Things you do on your device have no effect on the server. If you read a message on your phone, then log in to Gmail, you will see that same message marked as unread. It may start to feel like Groundhog Day.

2. A two-way communication path (IMAP). Unlike with POP, your devices talk back to our servers and sync your changes automatically with IMAP. When you sign in to your Gmail account in a web browser, actions you've taken on your email client or mobile device (like putting a message in a 'work' folder) will also appear in Gmail (your message will already have a 'work' label on it). This all happens automatically once you set up IMAP, so you don't have to read or sort all your mail twice. This is really helpful when accessing Gmail from multiple devices.

Here's a quick rundown of the key differences between IMAP and POP:



As you can see, the benefits of IMAP clearly outweigh those of POP. To set up IMAP, just follow these steps.

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Great performance has always been an obsession at Google and it's something that we think about and work on everyday. We want Gmail to be really fast, and we keep working on ways to make it faster. Gmail's architecture eliminates many of the delays in reading mail by employing techniques like prefetching, but recently we decided to take a close look at some other key parts of Gmail to see if we could speed things up.

One of the areas we worked on was the initial loading sequence: everything that happens behind the scenes between the time you press the "Sign in" button on the login page and the moment you land in your inbox. While the improvements we made won't resolve every "This is taking longer than usual..." message you might see when loading Gmail over a slow connection, we've seen a real reduction (up to 20%) in overall load time compared to when we started.

First, we listed every transaction between the web browser and Google's servers, starting with the moment the "Sign in" button is pressed. To do this, we used a lot of different web development tools, like Httpwatch, WireShark, and Fiddler, plus our own performance measuring systems. These tools all have useful features, although some are limited to working only with certain browsers. The Httpwatch plug-in for Internet Explorer was one that proved easy to use and provided us with most of the information we needed. It really helps that we can capture and save browser traces with it too.

We spent hours poring over these traces to see exactly what was happening between the browser and Gmail during the sign-in sequence, and we found that there were between fourteen and twenty-four HTTP requests required to load an inbox and display it. To put these numbers in perspective, a popular network news site's home page required about a 180 requests to fully load when I checked it yesterday. But when we examined our requests, we realized that we could do better. We decided to attack the problem from several directions at once: reduce the number of overall requests, make more of the requests cacheable by the browser, and reduce the overhead of each request.

We made good progress on every front. We reduced the weight of each request itself by eliminating or narrowing the scope of some of our cookies. We made sure that all our images were cacheable by the browser, and we consolidated small icon images into single meta-images, a technique known as spriting. We combined several requests into a single combined request and response. The result is that it now takes as few as four requests from the click of the "Sign in" button to the display of your inbox.

We hope that some of you have felt the change, but performance improvements often go unnoticed, and that's okay. We'll keep working to make Gmail faster -- there's a lot we're doing right now -- and we'll give periodic updates as we get improvements out. (And hopefully you'll notice some of them too.)

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The sight of someone scrolling through hundreds of email messages trying to find a specific one is like fingers on a chalkboard for me. With a few tricks, you can use Gmail to find the exact message you're looking for, without all the scrolling.

If you don't get a ton of mail, just typing in the words you're looking for usually does the trick. I can just type lisa in the search box and get all of the messages from my friend Lisa, southwest to bring up my ticket confirmations, or "bank statement" to help get my finances in order.

But the real power of Gmail search lies in search operators -- words that help modify your queries. Search operators work pretty much the same way within Gmail as they do for Google. So, if I want the email Lisa sent me with her flight information so I know when to pick her up at the airport, I type from:lisa SFO. Likewise:
  • A link from my co-worker Michael: from:michael http
  • A photo from my mom: from:mom has:attachment
  • That last chat I had with one of the Gmail product managers: keith is:chat
  • All messages from ebay that aren't outbid notices: ebay -outbid (the hyphen tells Gmail to return all of the messages that don't contain the word that follows it)
  • The messages in my inbox sent directly to me that I haven't read yet: to:me is:unread in:inbox
You can limit the scope of your search to a particular subject (subject:) or label (label:) as well. And you can get pretty fancy. Recently, I was trying to remember the date of my friend's April birthday. I always send her a birthday email, so I searched to:maya (birthday OR bday) after:2007/4/1 before:2007/5/1. It's the 19th.



If remembering operators isn't really your thing, that's ok. There's a "Show search options" link to the right of the search bar at the top of your inbox.



Clicking that provides you with text fields you can fill in to get the precision of advanced search. Start there, but after a while you'll probably find that using operators is a lot faster.