♠ First my opinion on what omnscient0 posted: I agree w/ most of what you just said. I'm not a big fan of social media but the blacklisting thing would be perfect! Specially because that way I would NOT have to contaminate my eyes w/ yaoi or het stuff (which btw thanks to the gods is very scarce ^^).
♠ Also, about the mass email thing: I believe if you were to use a CMS on the site like drupal, joomla or even phpnuke (if you want to go very old school) you can get it going quite easily. I think that setting up a weekly email would reduce the traffic a bit since there'd be no need to come to the site and check for updates every single day (not that it would work for people like me who has the reader as home page :P … but for normal people it might). Anyway! Now onto my suggestions:
♠ I think that in addition to having “Read” and “To Read” lists we could have a “Favorite mangas“ list or even a “Favorite authors” list. I cannot be the only one that have a manga series (or a few) and reads it every once in a while. This would be especially helpful since the number of series/one-shots/volumes that are hosted here keeps increasing and has no end in sight (let’s all pray now :p ).
♠ What about having the option to mark a chapter as “Read” without adding the complete manga to that list? This is quite troublesome with ongoing manga series.