a top level domain without country association
Is .us considered a generic Top Level Domain and how does it affect my ranking?
How to create own generic top level domain?
What difference does the top level domain name make?
First of all, don't focus on choosing a top level domain with regards to ranking because TLDs don't really matter for ranking. Second, the use of unrestricted generic TLDs (.com, .net, .org, .info) doesn't adhere to their original intentions at all anymore, so you don't need to be a business or network provider to use them. For a blog about an idea, any of them will work (for example http://www.agilemanifesto.org/)
Instead, think about who you're writing for and choose a domain name and TLD that will be meaningful and easy to remember for them. Another rule of thumb - if there's already an established presence on a TLD you want don't just use another TLD; if it's an inactive site go for it, but if they're actively associated with the name then it may be hard to unseat them.
ICANN is also releasing loads of new gTLDs all the time. You can also delve into the popular country level domains (.io, .ly, .me, .es, .is, etc)
More on reddit.com