The following is straight from wikipedia.
Yahoo Mail, a web-based email service, launched in 1997 through the American parent company Yahoo. Yahoo Mail provides four different email plans: three are for personal use (Basic, Plus, and Ad Free) and another is paid-for business use.  By December 2011, it had 281 million users, making it the third largest web-based email service in the world.
So…what is Yahoo actually good for, versus what it promised to be able to do? Not much, and as far as the ‘stats’ of it being the largest, I use mostly Google/Chrome/Gmail these days, and that is primarily why. It SUPPOSEDLY has that is listed below, but as a long time use on more than one yahoo account, I can assure you the information is wrong and/or incomplete. As far as I can tell, the account expiration is no longer, but haven’t checked my ‘other’ accounts so can not say with total certainty. The pop3 ability has not worked for ages, with notice after notice that can no longer connect gmail, although had it connected and was told it no longer was available and now get almost constant spam from them to connect the two. The most wrong of the wrong is the 100 filters, spam and virus protections. I erased all of mine because it was not working right, and had not been, as I get almost constant spam, many of which have blocked in SEVERAL ways. Even after a new start, it only allowed about 6 entries and then went back to not actually putting ANY of them in there, no matter how many times or ways have filtered and/or blocked them. I click dozens of ‘spam’ every day with them, and each new day or even later in the same day, get the SAME type spam back, sometimes even to exactly as in same sender, same email, ad nauseum. I block them as well, when it says can, which is almost all the time, but it never blocks any which is all the time.
Email storage capacity: 1 TB.
Email attachment limit: 25 MB (up to 100 MB via the built-in ‘Attach Large Files’ app).
Account expiry on inactivity: 12 months. The account cannot be retrieved.
Supported protocols: POP3 in Asia or via YPOPs!, IMAP via IMAP proxy or via Zimbra, SMTP, Mail Forwarding in some countries. US Users gained free POP3 and Forwarding access in 2013.
100 filters to automatically sort incoming messages (200 filters for the Plus version).
Spam and virus protection. (See: DomainKeys)
Advertising is displayed on the screen while working with the email account. Text ads are added to the footer of outgoing messages, as of February 2011.
Yahoo has had 3 or 4 ‘data’ breeches in as many years or less. Yet their ’email’ can’t even block or set as spam or phising ANY of those, no matter how many times and ways the user tries. Yoohoo Yahoo, Verizon even at their dropped offer price, is still buying even more of a mess whan they already are, and with your ongoing data breeches, no telling how many android phones and others will suffer the consequences and time lost. It’s time, past time, for yahoo to go the way of the dodo and netscape; evolution has spoken. Computer tech, past and present, have spoken; I represent those and others who are fed up with your overall incompetence that is so bad you can’t even do the basic functions of email provider, worse putting the rest of us time after time in financial harm’s way.