You'll get that on most IM services these days. Skype, AIM, and even XMPP and Google Hangouts...They're all seeing a surge of spam anymore. That's the sad thing about keeping good, open IM protocols: assholes abuse them.

Yahoo messenger was officially discontinued and probably isn't moderated any more, so that's not a bad idea.

Was it? Certainly didn't get as much press as MSN.

yeah, it was discontinued around the time of Vista.

Since when? I know the public chats were killed off, but the messenger protocol and system are still actively maintained.

well, I'm just going off of the wikipedia article and the fact that there have been no updates whatsoever to any of the clients.
See: release history

http://en.wikipedia.org/wiki/YIM

Ah! You're going by the client's status. The protocol and system itself are maintained quite well, but no, the first-party client isn't as well maintained right now. The most recent release was in march 2012, though. However, I think you're confused by this:

Yahoo released a preview version of Yahoo Messenger for Windows Vista. It had been designed to exploit the new design elements of Vista's Windows Presentation Foundation and introduced a new user interface and features. It lacked some basic functions such as webcam support. It has since been discontinued.

That's actually referring to a WPF (Windows Vista/7 Native) version of Yahoo! Messenger that was in the works, but discontinued. The actual client itself hasn't been discontinued outside of Linux. In fact, looking at my phone, the latest release of Yahoo Messenger for iOS was 07/09/2013, at least on the Japanese iTunes App Store.

I can see why you'd be confused about that, though. That's one reason I try not to rely on Wikipedia for anything.

ah, well, they haven't updated any desktop clients, then. the mac client I had hadn't been updated for years.

My old yahoo name got hacked and they refused to give it back :| So I only use my secret yahoo for mail now, and just skype and steam

Not really, my old yahoo has been hacked twice in the past month, so I transfered my contact lists to my new yahoo. Besides, I'm not on long enough to chat with anyone anymore. *Hugs You*

I know I ain't on your Yahoo (but I can be if you want~ ;3).