You can't really say that, Wynona, Yahoo in its heyday can be extremely useful, it had been for me.
But after the decline, weird things began to happen. Or perhaps after those weird things happen, Yahoo began to decline. Difficult to say what is cause and what is effect.
The most serious issue was the gigantic data breaches. Lucky me, I never filled in my profile.
en.wikipedia.org
The second most serious security issue was the Yahoo groups. As a security precaution, I accessed them with a web browser, and I never had an incident. Nearly all others accessed the Yahoo groups with an email client, because the Yahoo group software offers a range of attractive delivery options to choose from, like individual emails, daily digest, etc. I personally never saw any incidents in the groups that I was involved in either (I co-owned 1 group, co-moderated 3 groups, and participated in up to 3 more groups, and yeah, that's a reflection how useful Yahoo was for me) However, Yahoo had a special group for group owners and group moderators. What gets posted in that special group makes you shudder.
The third most serious security issue was Yahoo email. As with the groups, I access Yahoo email with a web browser, and I never had an incident. There was a really really angry, really really big mob about Yahoo email, but after a while it was only noise and no signal, so I shut it out and don't really know what happened.
Yahoo closed down all groups a couple of years ago, and my use of Yahoo came to an end. So yeah, now there is a dead mouse in the attic, and how to get rid of it safely.