Pokegee

Could someone please explain to me why Marth is commonly shipped with Ike on the internet? I get that they were in SSBB together, but Marth was with Roy in melee, and now there's Robin and Lucina as well. Marth and Ike have little in common and neither one is gay, but people still ship them. Just to be clear, I'm not stating any opinion on the shipping of these two characters other than confusion.