The official Node blog has a post about issues scaling npm: Keeping The npm Registry Awesome. It explains some of the recent downtime and outlines plans to improve the situation.
The root cause of these downtime was insufficient resources: both hardware and human. This is a full post-mortem where we will be look at how npmjs.org works, what went wrong, how we changed the previous architecture of The npm Registry to fix it, as well next steps we are taking to prevent this from happening again.
The post is relatively lengthy and buried at the end is a plea for funding:
But we need your help! All of these necessary improvements require more servers, more time from Nodejitsu staff and an overall increase to what we spend maintaining the public npm registry as a free service for the Node.js community.
Please take a minute now to donate at https://scalenpm.org!
By burying the funding plea at the end the author was presumably trying to avoid making the post sound spammy, but seeing as most people don't read anything on the Internet I thought I'd reiterate the point because I'm not scared of sounding spammy: DONATE TO NPM! SAVE FERRIS!
If you pledge $75 you'll get benefits, like $25 credit on Nodejitsu or Iriscouch. Sounds good to me!