[msabalau]

Yahoo doesn't necessarily have to bolt onto Tumblr onto a dying core, one option would be to milk yahoo.com (and leverage whatever synergies exist) to invest in Tumblr as a new and seperate replacement core.

Maybe not likely, and maybe not enough "there there" to build an appropriate sized business around.

[xur17]

I really hope they don't try to bolt it onto their existing site. Like you said, I think they'd be wise to grow it separately.