You can search to join yahoo group page. Yahoo groups help to know most useful information. Learn how to search yahoo mail groups.
1. Open your web browser and type your address bar yahoo.com and press Enter button from your keyboard.
2. You see yahoo home page. Click Groups button to search a yahoo group. This button you see up forth button into yahoo home page.
3. You see yahoo group page with Search Groups box. Click Search Groups box and type any group name as you want to search. Click Search Groups button to search yahoo group.
4. You will see few group pages. Click a page to watch it.
5. You also see few buttons behind of Groups. Click Best match, #of members, Latest activity, Newest first and Oldest first to watch this group page.
Using this way you can find out most popular yahoo groups.