Yes, you need a Yahoo account to create a Flickr account. Flickr was owned by Yahoo, and the sign-up process for Flickr requires users to log in with their Yahoo credentials. If you already have a Yahoo account, you can use it to access Flickr directly.
Yahoo.
There are a lot of websites that use Yahoo ID's such as: Flickr, Yahoo Answers, Delicious, MyBlogLog and others.
Flickr was created by Ludicorp and co founded by Stewart Butterfield and Caterina Fake. Flickr was acquired by Yahoo in 2005. Both Stewart and Caterina resigned in 2008.
On Google Images, Yahoo! Images, and Flickr
FLICKER
Yahoo! own several branded companies and four companies without the Yahoo! name. The unbranded companies are Tumblr, Flickr, AdInterax, and Rivals.
Yahoo is the owner of BT's email services. This doesn't necessarily mean that the entire website is owned by Yahoo, but a certain part of it is in fact.
Yes. They are owned by different companies.
Yahoo hasn't made any tangible products. However, Yahoo does own many websites and services. This includes AdInterax, Flickr, Rivals, Tumblr, Upcoming, and FoxyTunes. Yahoo also owns many websites that are branded with the Yahoo! name, such as Yahoo! Answers, Yahoo! Mail, Yahoo! Finance, Yahoo! Messenger, and many many more.
Yahoo! has come a long way from the days when all they did was provide email and search services. Today, Yahoo! is the owner of such recognized brands as photo-sharing service Flickr and blogging platform Tumblr.
There are a large number of image sharing websites on the Internet. Among them, Photobucket is considered pretty highly. Flickr, owned by Yahoo, is also considered pretty highly. There are multiple others as well, but both of the aforementioned sites offer free accounts.