Extremely dependable
Since I abandoned Hotmail due to spam, Yahoo! has provided by far the best freemail service I’ve seen.
I have used Yahoo’s other services minimally, so the benefits others might realize from having a Yahoo ID are somewhat lost on me. But signup is quick, simple, and requires minimal information.
Using the service is very straightforward, and offers nearly as much customization as Hotmail, surpassing it in some areas. One rather odd note, you set the width of your composition box between 50 and 99 characters wide, but it is limited to a mere 15 line height
No web service, especially a free one, is immune to outages, but I have found Yahoo to be extremely reliable. I have never had messages deleted due to a server malfunction, nor do I read constantly about security holes in the service, as is the case with certain other providers.
Certainly not to be overlooked is the 6 megs of available space. This has allowed me to keep my all personal email (incoming and outgoing) on Yahoo for the past year, without nearing the space constraints. On a somewhat related note, if you have a tendency to go into your trash folder to undelete mail, Yahoo’s trash folder does not empty itself on a regular basis, but rather only when you are nearing your mailbox limit.