Self Publishing Book SitesSelf-publishing book pages
Write books: Which are the best web sites to post a book on-line?
Dependent on where you are (since the query is in English, I will reply for the US/UK markets;-) and since your query is ".... post a book yourself online", I suppose, eBook (with the option to print?): Lulu, Smashwords, Kindle Direct Publishing (KDP, Amazon) - I know (or work with) them and I've been hearing about Bookbaby.
They can also consider Apple (iBooks, but you need a Mac computer) and Google Play (Books) if they are not included in the above list of vendors (or if you get a higher percentage by filing directly to them, a default example is KDP). However, there are many more (serious) eBook deployment sites.
Look out for "publishers" distributors / service providers who demand a high prepayment and do not fairly divide the winnings. When you want to post in another countrie / another languages, you have to be more specialized (e.g. the English linguistic markets are in relation to self-publication with many available tools, e.g. Tolino Media, KDP, BoD,....).
Are self-publishing sites good for authors other than Kindle?
You don't need a self-publisher like Lulu, Outskirts Press or many others who are looking for writers for printed music. Every one of these enterprises has its own strong and weak points. Expanded sales are more costly than Ingram (60% vs. 55%) and since their accounts cannot be taken back, they are not affected by the bookshops.
The Ingram Spark Group has a much more resilient global supply chain, and the bookshops are pleased with specific order backlogs because they are reusable. Self-publishers " exists for one reason: to free writers from their gains and resell them on useless advertising efforts. You wrap writers with the promise of cheaper book publishing or "do-it-yourself templates", but the writers quickly realize that these commitments are not being kept.
Do not use CreateSpace or other self-publishers to modify or create your book, and do not do it yourself. It' s going to look poor and join the ever-growing flood of horrible novels that have been mispublished in the false way themselves. Traditionally, the publishing house has invested in the book, hired professionals to make the book to industrial standard, paid the inevitable dealer rebates when a book is purchased, and amortized this return by retaining the lion's share of the profit and paid the writer a small license fee for each copy purchased.
Authors take on the publishing roles as described above in the case of legal self-publishing and then retain all gains for each book they sell. You do not even profit from the author's bookstores. Self-publishers " are inadmissible. You calculate the book preparation fee to the writer AND you keep the lion's part of the winnings and pay a small license fee to the work.
There are more writers to ask: "What makes this firm eligible for a percentage of my profits?"