In addition to the others suggested, I recommend Cece Moore's blog: http://yourgeneticgenealogist.com/
- she updates regularly and is very fair in her coverage of all the major companies. (Fair with both praise and criticism where due.)
VERY SHORT VERSION OF LONG POST BELOW: Until raw data is released, just treat your Ancestry DNA matches like any other traditional genealogy hint. There's nothing else you can do at this time (but that's changing soon).
THE LONG VERSION:
I'm assuming that you took Ancestry's new(ish) autosomal test, not the yDNA or mtDNA. (The current structure of these forums doesn't differentiate, alas.)
If the only place you have tested is here at Ancestry, all you can really do for the moment is prepare for the future by using traditional genealogy:
1. Look at your matches' surnames and locations for items in common. Take notes if you see any connections or potential connections.
2. Look at your matches' other surnames and, time permitting, their entire tree, for any collateral surnames that might ring a bell. (Also, you might see surnames for more distant ancestors in your tree. If your ancestor was part of a community with intermarriage, this may be relevant, even if it's not within 10 generations.) Again, take notes.
3. Although it's a good idea to start with your closest matches, don't ignore the more distant matches. Many of us have found dozens of connections there.
4. Contact people if you'd like to share theories on possible connections or if you have questions about what you see in their tree, just like with traditional genealogy.
When Ancestry offers raw data, all of your observation, note-taking, and possible communication with matches will finally pay off.
Until then, every "paper trail connection" you see is only a possibility; your actual DNA connection could be somewhere else entirely.
Ancestry hasn't said anything yet about definitely providing a segment comparison tool, but they have said they'll give us raw data in "early 2013." So, assuming that's all we'll get for awhile, here are some probable next steps:
1. Upload your raw data and GEDCOM to GEDmatch. (Free, volunteer-run website. Donations appreciated. They'll probably work quickly to accommodate whatever format Ancestry's raw data takes.)
2. Use GEDmatch's many tools to look at the following:
a. Other matches who share the same chromosome segment. (Find out what they all have in common. A surname? A place? Do your matches match each other? Soon you will have theories about which ancestors your different segments represent.)
b. Ethnicity (admixture). GEDmatch has several tools for breaking down ethnicity using different methods. Curiosity aside, this can be useful when you're comparing yourself to your matches, especially if you haven't had a parent test. If some people who match you on chromosome 3 at position 12000000 and show Siberian ancestry in that spot, and some who match in the same spot show North Atlantic ancestry, you can probably assume that the first group matches one side of your family and the second group matches the other.
c. You can also use a tool to compare your GEDcom to all of your DNA match GEDcoms that can be useful. (For my husband, an Australian with a medium-sized tree, this was a nice feature. For me, with my jillion colonial ancestors, it was hundreds if not thousands of false matches to incredibly common names.)
d. You also get lists of all your matches, which will include people who have tested at FTDNA and/or 23andMe. Those matches may not have a GEDcom, but you can email them to start a discussion.
e. Make comparisons to matches in common with other matches using the triangulation utility, which I won't explain because I find it so cumbersome that I'm sure I'm using it wrong if I find doing it by hand to be easier, haha. :)
3. Possibly also upload your data to FTDNA. (FTDNA says it plans to allow transfers from Ancestry when Ancestry makes raw data available. Right now it costs $89 to transfer from 23andMe.)
Why upload to FTDNA when GEDmatch is available? Because, unfortunately, not everyone joins GEDmatch. Also, FTDNA has a more user-friendly interface than GEDmatch. (But again, GEDmatch is free, has more tools, and will match you to participating 23andMe people as well.)
4. Convince all of your Ancestry matches to participate in GEDmatch. LAISSEZ LES BONS TEMPS ROULEZ! ;)
So, with step 4 in mind, hopefully Ancestry will create a robust in-house segment comparison tool themselves. If they do, they will surely emerge as the instant leader in autosomal testing. No one else comes close to the way they nicely integrated trees into the DNA Match pages, something which REALLY spoiled me when I went from here to 23andMe and FTDNA.
Anyway, don't feel overwhelmed - the overwhelming (but amazing) part is yet to come! :)