I've been a Yahoo Mail user for about ten years, and then I started switching to Gmail. My biggest motivation for switching wasn't usability. It's that I picked a really dumb user name for Yahoo (daveny1024), and I picked a much better one (dberkowitz) for Gmail, though I did wind up preferring Gmail once I got used to it.
I still held on to Yahoo for awhile, but it's been more of an added hassle to keep. I didn't want to delete all the email entirely. Yahoo engages in a form of highway robbery here though. In order for you to export mail from Yahoo, you need to pay $20 annually for Yahoo Mail Plus. This must be afoul of some antitrust statutes; if there's no charge for switching your mobile phone number between carriers, there shouldn't be one for backing up or changing email. Still, the $20 is worthwhile to ultimately spare you from keeping another email address handy.
I read a few help files on switching, but they all seemed too technical or too simple. There were a number of things I had to figure out myself, sometimes after taking a couple wrong turns. I've created a guide below for switching from Yahoo to Gmail, one that's especially helpful if you have a lot of mail from Yahoo you want to hold on to. Here it is:
A Pack Rat's Guide to Moving from Yahoo to Gmail Once and for All
* Create a label for anything currently in your Gmail inbox before setting up your Yahoo mail account. If you have a lot of Yahoo mail in different folders, you'll be very happy with this step. Once you've tagged everything in your Gmail inbox with that label, archive it. You can then move it back to your inbox later.
* Sign up for Yahoo Mail Plus. Pay the $20 extortion fee. If you really don't trust Yahoo, or are wary of whoever might own Yahoo in time, set a reminder in your calendar for nearly a year from now to cancel your subscription before it renews.
* In Yahoo Mail options, go to POP & Forwarding and have it set to Web & POP access. You shouldn't need to do anything here. Through this, you can also view the POP settings, but Gmail populates this automatically.
* Go to Gmail > Settings > Accounts and click "add another mail account." Once you enter your Yahoo login, everything will be set up for you. You won't need the settings from Yahoo at all.
- Bonus tip: as you're importing your mail, sometimes you'll find Gmail won't check it instantly. You can go back to the Accounts tab and click "check mail now" by that account to speed it along.
* Create a filter in Gmail that says any mail from your Yahoo address gets tagged with the label "yahoo mail" (or something like that). It can come in handy for sorting through things later, though it's hardly a must.
* Any mail in your Yahoo inbox should start coming in, and once Gmail imports them, they should get out of your Yahoo inbox. If there's anything to respond to, either respond to it here or tag it with the "gmail inbox" label you created earlier. If nothing's important, you can archive it, or tag it with existing labels. Your goal should be to archive all of this before continuing, as it will make your life much easier if you have a lot of folders.
* You should now have empty inboxes in Google and Yahoo. Just take a moment here to check on that, and if not, review these steps again or think what else may be holding you back.
* Now, go in to your first listed folder in Yahoo and drag everything into the inbox. Gmail will soon import it, or you can go into your Accounts tab and have Gmail check it sooner.
* Once it arrives in Gmail, create a label for it similar to what you had in Yahoo, or (better still) use an existing label in Gmail if you've already created one. Archive all of it, again keeping an empty inbox. You can always click on the labels in Gmail to make sure you have everything. I know, it's a big step, so it's worth double-checking it's all going well.
* Do this for every folder in Yahoo, but one folder at a time. I learned this the hard way, trying to import a few folders at once, and it was a mess.
* Set up a vacation autoresponder in Yahoo to say you're now using Gmail. You technically don't have to, since your mail's coming to Gmail anyway and you can respond to people as needed. But if people are still writing you there, you can let them know they should update their address book.
* Before a year is up, unsubscribe from Yahoo Mail Plus and stop paying them blood money.