I am looking to purchase a software (suite?) comparable to
"BuildACommunity" (see http://www.buildacommunity.com/) that has been
developed on the .net framework, ideally using vb.net. Specifically, I
need a program that parallels their AutoHomepage module and I would
prefer to find a suite that has similar multi-functionality to that
found with BuildACommunity.

Question: What are the direct competitors to AutoHomepage built on the
.net framework?

Question: What are the direct competitors to BuildACommunity built on
the .net framework?

Please take a look at the AutoHomepage information on the
BuildACommunity site to become familiar with its functionality. I
don't just want site hosting - I want specifically for the constituent
groups that comprise my association to be able to create their own
templated sub-sites on our larger site without a knowledge of html and
with minimal to no oversight/administration from us as the webmasters.
Please ask questions to clarify if needed.

This is my first answer type of thing and for some reason I can't
enter an answer.  Anyways, I'm suprised no one has answered you yet. 
There are currently two products that have been developed that would
probably meet your needs.  Most likely the best product would be
DotNetNuke (http://dotnetnuke.com) or RainbowPortal
(http://rainbowportal.net).

Both of these portals are based on the IBuySpy.net starter kit but
have been much improved since.  DotNetNuke sets the bar for N-Tiered
web development.  Personally, I prefer the DotNetNuke portal because
of the code that its written in VB.net and, from what I can tell,
seems to have a broader range of support.  However, I've heard nothing
but good things from people that use the rainbowportal kit.

I'm going to focus on DotNetNuke for the remainder of my comment here
as it meets your request for an asp.net/vb.net application.  One of
the coolest features about the DotNetNuke site is the fact that you
can create sub sites based on a master site which you, as the primary
webmaster, would setup.  Each sub-site would have its own
administrator that would be able to add and remove
permissions/users/features on individual modules and and subsites,
allow them to "skin" their site anyway they would like, build all
sorts of custom news, blogs, calenders, documents, images, newsfeeds,
image galleries, etc. anywhere they wanted on their site.  You don't
need to know any html in order to build a DotNetNuke site, you just
have to play around with some of the settings and read a bit in the
forums and your good to go.  The DotNetNuke portal is just about fully
documented among different developer sites and here
http://www.dotnetdoc.com/Default.aspx?tabid=29 and here
http://www.dotnetnukehelp.com/DesktopDefault.aspx.

The beauty of DotNetNuke is the scalability of the application. 
Pretty much anything that you can think of in terms of cool web
applications has already been done and can be added to your portal. 
There are many third party free and supported "modules" of DotNetNuke
which let you customize which features are available for your sub
sites.  For example, http://snowcovered.com and
http://www.smcculloch.net/Default.aspx?tabid=40.

Finally, there are about 50,000 registered users of DotNetNuke and
about 65,000 posts about this product are here
http://asp.net/Forums/ShowForum.aspx?tabindex=1&ForumID=90 so the
community base that's available for support and troubleshooting is
pretty broad.  Oh yeah, and its completely free, 100% Community
Supported, Built and Maintained.

Finally, this is completely my two cents, I wasn't very impressed at
all with the buildacommunity and autohomepage stuff.  I guess if you
spend the 3 months writing your CSS's and positining your tables it
would be cool, but who wants to spend all that time AFTER you buy the
product?  If you're looking for linux stuff
http://typo3.com/Demo.1245.0.html or http://phpnuke.org.  Check out
http://hotscripts.com for more info.

Anyways, hope this helps.

Thanks for the guidance. I am familiar with dotnetnuke, but it doesn't
seem to have the features that I am looking for. Although you can
create a ton of subwebs, it doesn't appear to be built so that those
subwebs are completely self-sustaining by a novice end-user. My
understanding (and it is quite possible that my understanding is
faulty) is that the webmasters for the subwebs would need to be at
least mid-level computer literate. We do not have time to hand-hold
people to support the 60+ subwebs (with 60+ webmasters) that we are
anticipating. As you note, it takes a bit of reading to be able to do
the things needed - we're looking for something that is completely
intuitive and provides guided help - even if it means that there is a
very limited feature set on the subwebs. Rather than sophisticated,
we're hoping for simple, elegant, and faultless!