Wow that didn't take very long at all! It seems that there might be a backlash against the acquisition already! Matt Mullenweg has posted on his blog that WordPress have seen as many as 72,000 blog migrations from Tumblr to WordPress in recent hours.
That's a huge difference compared to the standard rate of between 400 and 600 per hour, but it's not uncommon when services such as Instagram were acquired by Facebook for there to be a huge migration of users and a backlash in general to the purchase.
Mullenweg added that:
"News like this, whether from a friend or a competitor, is always bittersweet: I’m curious to see what the creative folks behind Tumblr do with their new resources, both personal and corporate, but I’m more interested to know what they would have done over the next 5-10 years as an independent company."
We'll have to wait for the longer term changes to see if the Yahoo deal will be detrimental to the platform. Lets hope that this isn't MySpace all over again!