tl;dr: Use this tool
I wrote into Yahoo support about this on 04/14/11 and they replied with a long version of 'No' (see below for details). First I threw together a quick shell script to convert the HTML source of a My Yahoo page into an OPML file which can be imported into Google Reader or most other reasonable RSS readers. As an excuse to learn some Ruby, I also coded a web based opml generator.
./my_yahoo_source_to_opml.sh ~/tmp/my_yahoo_feed_source.html ~/tmp/yahoo.opml "Title of import folder"
my_yahoo_source_to_opml.sh source code:
if [ $# -lt 2 -o $# -gt 3 ]
echo 'Usage: ./my_yahoo_source_to_opml.sh /path/to/my_yahoo_source.html /path/to/output.opml ["Title of import folder"]' >&2
echo '<?xml version="1.0" encoding="utf-8" ?><opml version="1.0"><body><outline title="'$3'" text="'$3'">' > "$2"
grep -o '"feedUrl":"[^"]*' $1 | sed 's|\\||g' | sed 's/$/" \/>/' | sed 's|"feedUrl":"|<outline type="rss" xmlUrl="|g' >> "$2"
echo '</outline></body></opml>' >> "$2"
Original Dialog with My Yahoo Customer Care
I would like to export my My Yahoo feeds, ideally as OPML. You
used to have an exporter, but it is marked as deprecated. Can you please
return my data to me? Thanks.
Thank you for writing to My Yahoo!.
I understand you want to export your RSS feeds from My Yahoo! in OPML
I'm sorry, but the feature you are describing is currently not available
on My Yahoo!.
Rest assured that I will pass along your input to the Product Team.
Please don't hesitate to provide us more feedback and suggestions as we
would love to hear from you. The Feedback Form below goes directly to
our Product Team:
Thank you again for contacting My Yahoo!.
My Yahoo! Customer Care