Who is the most popular self publishing company in the US or Canada?

Many sources name AuthorHouse (formerly known as 1stBooks) as the
largest self-publishing company:

"The 'Chronicles of the End Times' series is published by AuthorHouse,
said to be the world?s largest self-publishing house."

ReveNews: Recent Micro Manufacturing News
http://www.revenews.com/micro_manufacturing.html

"Based in Bloomington, Indiana, AuthorHouse has grown into the world's
largest self-publishing house, providing premier publishing and
marketing services for authors."

Shambles: Create and Sell your own books online
http://www.shambles.net/pages/learning/EnglishP/publish/

"With over 27,000 books in print, AuthorHouse is the largest
self-publishing house in the world, providing premier publishing and
marketing services to authors. The company was founded in Bloomington,
Indiana in 1997 to fulfill the dreams of authors who wanted to have
their books published while retaining all rights and control of
content. AuthorHouse provides high-touch customer service, an
easy-to-use process and a broad range of services to help authors
write, publish, distribute and promote their works. AuthorHouse titles
are available for order at more than 25,000 retail stores worldwide,
through major Internet booksellers and at the AuthorHouse online
store, http://www.authorhouse.com "

WebWire: AuthorHouse Author is Leacock Finalist - Again
http://www.webwire.com/ViewPressRel.asp?SESSIONID=&aId=2029

The Google Directory and The Yahoo! Directory are good resources for
locating the websites of self-publishing companies:

Google Directory: Business > Publishing and Printing > Publishing >
Self-Publishing > On Demand
http://directory.google.com/Top/Business/Publishing_and_Printing/Publishing/Self-Publishing/On_Demand/

Yahoo! Directory:  Business and Economy > Shopping and Services >
Writing and Editing > Self-Publishing
http://dir.yahoo.com/Business_and_Economy/Shopping_and_Services/Writing_and_Editing/Self_Publishing/

My Google search strategy:

Google Web Search: "biggest OR largest self publishing" 
://www.google.com/search?hl=en&q=%22biggest+OR+largest+self+publishing%22

I hope this is precisely what you need. If anything is unclear or
incomplete, please request clarification; I'll be glad to offer
further assistance before you rate my answer.

Best regards,
pinkfreud

great

I'd also like to suggest that you look into actually trying to sell
your book to a publisher. While it is, indeed, very difficult to get a
positive response-especially if you are a first time author- there are
many financial benefits.

For starters, most self-publishing goes through a subsidy publisher,
otherwise known as a 'vanity' publisher. These companies publish
anything- no matter how bad- as long as you pony up the money.  The
problem is that unless you just want some copies for yourself (and
they might require you to publish a set minimum) you will end up
paying a lot up front (up to several thousand) and end up having no
one to sell to. Places like Waldenbooks really only purchase from
known publishing houses, and without having your own market for the
book, almost no store will want to try you out.  If you have a market
that you have already created- for example if you have an online site
with lots of traffic- and you have a niche of interested consumers,
then you might do well self-publishing anyway.  But if you don't
already have a good market or at least a good idea of how to capture
that market, you might end up having no one to sell to.

Remember, even if your idea is great, and even if you are a good
writer, none of that will matter without getting your book to market. 
Just because there are 'big' self publishing places out there doesn't
mean that they are worth your time and money.

A good approach would be to first write a book proposal that outlines
what your book is about and how you believe it may be worthwhile for
the publisher to print. I'd also have a chapter excerpt of the book.
Send this with SASE to the publisher (good leads can be found in this
year's 'Writer's Market'- go to www.writersmarket.com) and think about
possibly sending out the proposal to multiple publishers (since it can
take them months to get back to you, if at all).  While this will take
time and you may end up getting no positive response, you avoid the
costly pitfalls of the self-publishing market. If you think you have a
really good book, consider finding an agent. An agent will usually
take a 15% cut, but they may also know where to look for publishers
better than you and they can negotiate better royalties.

Of course, if all you want is to publish a few copies of your book so
that you can have it lie on your coffee table for friends and family
to see, then by all means consider self-publishing. Just be aware of
the possibility that you might end up paying a lot of money for it.

Best of luck to you.

Please do some research on individual self-publishing houses before
you decide you want to work with them. A number of them have a very
bad reputation, including a few mentioned in Pinkfreud's excellent
answer. Just because they are the best known or the "biggest" doesn't
mean they treat their authors well.

Kriswrite