If you’ve ever connected an IMAP email client like Apple Mail or Mozilla Thunderbird to Gmail, you know it can do a few weird things: Deleting an email from the client will usually remove it from the Inbox, but won’t actually delete it from the server – the email lives on in the All Mail folder instead of actually going away. IMAP clients also create and use their own Drafts, Trash, and Sent folders by default, instead of Gmail’s built-in folders.  Because of this, drafts saved in the IMAP client can’t be edited in the Web client (and vice-versa) extraneous labels are created in the web client, and in general things just don’t mesh as smoothly as they should unless you know which settings to change in which client.

Enter Sparrow, which was built from the ground-up with Gmail users in mind – it shows threaded email conversations, it works around all of Gmail’s aforementioned idiosyncrasies, and it does so in an appealing minimalist package without any additional finessing or configuring. The 1.1 update even adds support for the Priority Inbox feature if you have it enabled.

Visually and functionally, Sparrow draws primarily from two things: the Twitter for Mac app, and the iOS mail client.

Sparrow displays all of your accounts vertically on the left-hand side of the app – to switch accounts, just click a different profile picture. Buttons are available for your main folders (Inbox, Sent, Drafts, Trash) and for basic functions (New message, Reply, Archive, Delete). Double clicking an email thread will open it up in a second window, where you can read all the messages, reply, and add or change labels.

If you want things to get even more compact, you can enable the “hide message preview” setting and fit even more messages into a given window.

If you hit the button in the bottom-right corner of the app, a message pane will slide out and you can view your emails without opening a second window. In this view, Sparrow is not much different from the iPad mail client in landscape mode.

You can star your messages as you normally would in Gmail, and your labels are denoted by small color-coded triangles. These triangles are pretty subtle and they don’t sync to the colors you have your labels set to in the web client, but if you’re a heavy label user you’ll probably get over these gripes.

Sparrow works best if you use Gmail without too many of the Google Labs add-ons enabled. People who rely heavily on, say, Multiple Inboxes or Undo Send (a personal favorite for so, so many reasons) may miss them in Sparrow.

Sparrow just wants things to be simple, and to that end you don't have to dig deep to find most of the program's advanced preferences. There are a few simple sort options – Inbox view is the default, but you can also choose to view your Priority Inbox or your unread messages, and you can also view messages by label or folder. You can label individual emails or move them to folders, though you’ll have to dig into your account settings a bit to actually create a folder or label.

Also buried in the account settings: the ability to create account signatures, setup aliases for your different accounts, and configure keyboard shortcuts – you can set your own for showing and hiding the program, and you can also tell Sparrow just to use Gmail’s default keyboard shortcuts.

Setting up a Gmail account is seamless and automatic, since Sparrow was built with that service in mind, but setting up any old IMAP account is as easy as putting in the proper server addresses and ports, same as any email client.

Once you’ve setup your IMAP account, it behaves almost exactly as does a Gmail account – labels are turned to folders, but you get your message stars and your conversation view and the nice, simplified interface. Depending on how awful your email account’s web client is, Sparrow could breathe some fresh air into it. By the same token, though, people who are already put off by Gmail's movement away from a traditional folder structure probably won't find Sparrow to help much, since your folders are buried a bit by default in standard IMAP mode.

One substantial difference between a Gmail account and an IMAP account: adding a label to a Gmail message will add the label to the message but leave it in the Inbox view, same as Gmail. Moving a message to an IMAP folder, however, makes the message disappear from the Inbox view. It's not that hard to wrap your head around, but could take some getting used to depending on how familiar you are with the way Gmail labels work - for new Gmail users coming from other email systems, labels can often be one of the trickier concepts to grasp.

Adding a label to a message in a Gmail account

Moving a message to a folder in a standard IMAP account

I like Sparrow a lot, but it’s going to appeal to a very specific set of users: heavy Gmail-centric email users with multiple accounts who need something that just gets you your email and then gets out of the way. For users who rely on feature-rich clients like Outlook, it may be a bit too streamlined; for current users of more traditional clients like Thunderbird and Apple Mail, it may be a bit too different. For myself, though, I can say that it presents a pretty good compromise between features and minimalism - it's easily the only email client I prefer to Gmail's web client.

Sparrow is available in several flavors: On the Mac App Store, the full version of Sparrow is available for $9.99. You can also download Sparrow Lite for free - this version, which only supports one account, is ad-supported and also inserts and mandatory "sent with Sparrow" tag in your signature. OS X 10.5 users without the App Store can download Sparrow from its Web site.