I'm a big fan of PackJournal. Hardly anyone uses it yet, but it's got a bunch of cool features for cyclists:

It has a free app (Android only) that lets you write your journals, save them offline, and upload them later, whenever you have a connection.
The app remembers when and where you wrote your journal, and once you get them online, all your journals and photos appear on a map.
Good privacy controls - if you only want certain people to see your map/photos/journals, you can keep it that way.
You can set up mail drops on the site and resupply yourself online, while on the road.
You can customize your page with FAQ's, gear list, or whatever else you'd like as a primary page.
You can put a fundraiser right on your page and raise money for a good cause, without donors even having to leave your page or sign into an account or anything.
You can keep a small amount of fundraising to help you pay for the trip (donors are told this before donating), so you can essentially be paid to tour and blog.

It's all free.