I'm wringing my hands over the future of my favorite mail program, Thunderbird, as its developers consider whether it should be spun off on its own. It's only my favorite program because it's proven itself in my work, however. Like most people, I usually access my personal e-mail through a web browser. This doesn't mean I've erased Thunderbird from my home computer's hard drive, though. Here are some powerful reasons for keeping a dedicated e-mail reader in your Programs folder:Checkboxes stink. Managing messages in web-based mail readers is a pain in the you-know-what. Even with those programs that have good search tools under the hood, if you want to select and manage multiple messages, you'll eventually have to check a jillion tiny little boxes...one for every message you want to modify. Until we see more AJAX-y web sites that support click-and-drag selection and drag-and-drop, mass message manipulation is always something that's easier accomplished in a desktop mail client. Your personal information needs a home. If you use a PDA or a smart phone, and are smart enough to want a safety net in case your pretty toy gets lost, you sync your data to your personal computer. If you use Windows, odds are good that when you sync all that information, the program you use as your conduit is a mail reader: Microsoft's Outlook. This is because lots of desktop mail programs can manage more than just your messages; they can manage a calendar, an address book, or a task list as well. Lots of Web-based mail readers offer tools for managing these types of personal information, but none of them have yet offered a way to get that information onto your organizer in a single step. Handheld manufacturers have been designing their devices to support Outlook for years. Sometimes, there's not a (network) cloud in the sky. Web-based e-mail takes for granted a connection to the Internet. What do you do if you want to compose e-mail when you aren't near a hot spot? As close as we are to ubiquitous connectivity, sometimes I don't have a network available. Even then, I still need to have access to the messages in my inbox. You are your own lifeguard. While we'd like to think we could trust our service providers to manage our data responsibly, this may not always be the case. I know a couple of people who lost messages and contacts from their accounts on a major Web e-mail system during one of the company's server maintenance periods a year ago. The service agreements that so many of us click through without reading often absolve the providers of any responsibility if anything like that happens. It's handy then to have the contents of your Web-based account archived in a desktop client. You're not paranoid if they're really out to get you. Every machine you store your e-mail messages on is another place vulnerable to subpoena or snooping. How many people do you want reading your mail? By downloading your mail into a desktop client, and deleting it from your provider's servers, you leave less of your business available to prying eyes.