What if it doesn’t arrive?

E-mail has never been a foolproof way to send information. Lately it has gotten even hairier, with well-meaning but overzealous anti-spam filters blocking legitimate messages.

If you’re sending something crucial, it makes sense to follow up with a phone call afterward to make sure it has arrived. This is particularly true if you’re sending a large file or files by way of an e-mail attachment. Internet service providers typically limit attachments in received e-mails to anywhere from 2 to 10 megabytes, which isn’t always large enough for presentation, photo, audio, or video files.

You have many options to choose from when e-mailing large files. But whatever method you use, it also makes sense to check with your recipients before sending the file as well. If you’re using a technology they don’t have access to or that would be difficult for them to use, you’ll turn online convenience into inconvenience.

Mailing a recordable CD with the file or files on it is almost universally accessible. Virtually every personal computer these days has a CD or DVD drive, and most also have a CD or DVD recorder.

If you want to transmit large files over the Internet, you’ll save yourself and your recipients some grief if you first make sure both you and they have a broadband connection (such as cable, DSL, satellite, or T1). I once neglected to do this; I later received a call from a peeved editor (who was still using a dial-up connection) letting me know that my e-mail attachment had tied up his computer for 45 minutes before the transmission conked out.

One broadband solution is to use an instant messaging program such as AOL Instant Messenger (http://www.aim.com), the free program from America Online that you can use without being an AOL subscriber. Your recipient also needs to use the program, though it’s available through a quick download.

Another solution is to send the file to a free Web-based e-mail account such as Yahoo! Mail (http://mail.yahoo.com) or Gmail (http://www.gmail.com), which download attachments using the Web HTTP protocol. (Your recipient will need to have such an account.)

If you and your recipient both use Microsoft Outlook Express, you can take advantage of its file-transfer feature, which can automatically divide a large file attachment into smaller pieces and send each in a separate e-mail message. The program then automatically reassembles the pieces in the recipient’s in box.

You’ll obtain faster transfer speeds if you use a technology specifically designed for transferring files, such as FTP (aka file transfer protocol). FTP has been around for a long time, and using it requires some technical savvy. A number of programs have FTP clients built into them, or you can use a dedicated FTP program such as the well-regarded CuteFTP (http://www.cuteftp.com).

If you’re already using an online backup or storage service, you can piggyback your file transfers on top of it. Streamload (http://www.streamload.com), for instance, makes it easy to e-mail recipients with a link they can click on to download your file or files, without their needing to use a special program on their computer. The service is free for up to 10 megabytes of storage.

But perhaps the best way to transfer a large file to someone is to use a Web site designed specifically for this. With YouSendIt (http://www.yousendit.com), you can send files up to 1 gigabyte in size; with Dropload (http://www.dropload.com), the limit is 100 megabytes. The former makes it easy to send files to multiple recipients, while the latter makes it easy re-send files to the same recipient at later dates. Both are free, advertising-supported sites.

One limitation of both services is that they let you send only one file at a time. You can overcome this by combining multiple files into a single file using the ZIP file compression protocol. ZIP utilities are built into many programs, including the excellent file manager PowerDesk from VCOM (http://www.v-com.com).

Or you can use a free stand-alone ZIP program such as ZipCentral (http://zipcentral.iscool.net), which lets you create self-extracting ZIP files, preventing your recipient from needing to have a ZIP tool.

WhaleMail (https://www.whalemail.com) doesn’t require you to ZIP files if sending more than one. It lets you store files on its server for up to 2 weeks and notify a recipient or recipients with a quick e-mail. Recipients are directed to a unique URL to download the file with their Web browser. Pricing starts at $20 per year for 10 megabytes of storage.