Here are my working methods so far:
a) Webclipper tool of http://www.evernote.com allows me to select text, right-click (when installed with IE browser; but Chrome, firefox, safari are supported, too; zotero for firefox has a similar tool) and choose "send to evernote." After I have collected a bunch of items as individual entries there, then I use File >Export as... html (to preserve hotlinks).
That batch of saved excerpts is now a single file that can go to Kindle via the free "convert" email service at Amazon, or using a program like Calibre or Mobipocket in order to make the kindle conversion to *.azw
b) Instapaper.com allows chunks of text to be sent via email to the free account you register. Alternatively, the button that can be installed on the "favorites" bar in the IE browser will send the webpage you are viewing in its entirety. Once you've gathered all the webcontent via email segments or bundle of full webpages, it is possible to put the result onto kindle for reading and annotating.
c) An ideal productivity tool would work with a wordprocessor like MS-Word to allow selection such as Evernote (above), except that excerpts get appended to a running Word document which can be saved in HTML or DOC to convey hotlinks. That saves the "export as..." step.
d) The most tedious way is to select >copy >paste excerpts into a wordprocessing document.
e) A small improvement on manually copy+paste is to use a webcapture tool like the one included in the full (paid) version of Adobe Acrobat: capture 1 or 2 levels of the homepage content as PDF with all links intact. Then export as HTML (or considering kindle's native PDF reading, just load the PDF "as is"). For full kindle functionality (text to speech, for example), though, the PDF can be sent to Amazon for free conversion & delivery as *.azw, though.
In addition, one blog writer recommended linkage between one's Twitter account and Evernote. That way selections from kindle can be "tweeted" to the Twitter list and simultaneously be added to one's Evernote account for each editing, exporting and so forth.