And why would they? If you're really talented, you could either go work for Google/Facebook/etc. (if you want a stable life), or start your own company (if you're adventurous). Yahoo was stuck in the purgatory somewhere in between.
Summly was none of those. They got one 17 year old dev, and a fairly-decent product they made basically no use of. I don't know how good D'Aloisio is, but he's not that good. Especially without the kind of status and support that could turn out a bold new product within Yahoo.
I know nobody wants to go work for Yahoo, but they spent 30 million dollars. Hire 10 self-directed, expert devs for $1,000,000/year. I promise you can find good people at that price.
While I don't know if all these dictionaries and calibrated weights of parameters were really worth $15M, I'm positive that such an IP was major reason of the acquisition.
Summly was not D'Aloiso's product in terms of development. He may have had the idea, but the technology was SRI's (the same guys who developed Siri), and IIRC, Summly had exclusive use of that. So please stop demeaning it as "some 17-year-old's app".
I don't think that Summly was a bad product, and I don't think D'Aloisio is a bad dev. I specified him alone because as far as I know he's the only one Yahoo acquired - SRI is great but Yahoo didn't acquire their devs or exclusive rights to their tech.
The question at hand is whether Yahoo got their money's worth, and I'm claiming that they didn't bring on enough relevant tech or expertise to justify the expense. That holds even if Summly, SRI, and D'Aloisio are all fantastic.
What does that even mean?
I wrote it that way to point out that I'm not calling D'Aloisio a bad hire or a bad developer. He's got a good reputation, and Yahoo News Digest (his big project there) was actually really well received.
Rather, it wasn't worth the commitment Yahoo made for him, because he wasn't taking on the kind of sweeping rework or major new project needed to help with the death spiral. It fit into the general pattern of grabbing shiny new things at high prices, without really chasing the outcomes in users or revenue that might have mattered.