Flickr has an estimated 87 million users [1], and Instagram has 100 million. Note sure what your definition of "second rate" is (quality or quantity?) but Flickr is much better quality than Instagram, especially after the recent update. Regarding email, Outlook, GMail, and Y! Mail are pretty much all tied at 290'ish million users worldwide, but Y! owns the top spot in the US [3]. Most of Y!'s media properties are #1 in their respective areas as well (News, Sports, OMG, etc).

[1] http://www.theverge.com/2013/3/20/4121574/flickr-chief-marku...

[2] http://instagram.com/press/#

[3] http://news.cnet.com/8301-1023_3-57543177-93/gmail-edges-hot...