23andMe announced today in this Community Post that there is a new feature available. You can now download all your matching segment data for any of your "Owned" profiles. 23andMe will prepare a file which shows which segments match with each of the profiles you own or are sharing genomes with. You will receive an email when the file is ready.
To use this feature you go to the Family Inheritance: Advanced and click the "Request an Aggregation" link which is just below the boxes you would normally fill with the people you wish to compare.
You will get a file that looks much like the file you get if you download your Countries of Ancestry file, but this has the exact segment start and stop points, instead of rounded as it is on the Countries of Ancestry. The genetic distance in centiMorgans will be rounded to the nearest tenth of a cM. A really nice feature is the file will contain the URL for each compared profile, which will be very helpful when you are sharing with more than one profile with the same name (and yes, this does happen to me more often than you would think!)
For myself, I will be sticking with using 529andYou, since that allows me to do the compares quickly between people who match my kits in the same segment. For other users of 23andMe who maybe don't spend quite so much time working with their segment matching data as I do (and really, how many people out there *do* spend as much time as I do at this?), this is a great new option.