According to DC# book was received 12/23, but Receiver has not marked as received.  I did not use PBS mail.  Is it okay to send a gentle reminder?

Yes but keep in mind that: 1 it doesn't mean it was delivered to the right house (one of the books lost to me shows a delivery scan but I never received the book) and 2 they might have been on vacation for the holidays and just haven't come home yet or had a chance to open it and inspect it. 

If you are paying for DC through anywhere but PBS you are wasting your money.  (Unless you are just using Paypal for convenience).  But if you are buying DC from the post office you are payign too much and the cost quickly adds up to more than a lost credit/book-especially since PBS only honors DC bought through them.  And because DC isn 't really reliable, they only honor it because the fee they collect covers credit refunds.

They could be out of town.  But I polite PM is never a problem for me.  But then I have been know to check the mail on the way out of the house, receive a book, and turn around and go back into the house to mark it received, so I don't get it when people forget to mark them received.

Since it's been over a week, I'd send a pm - just something like "I just wanted to make sure the book got there ok" is fine.  Lots of people are really busy at the holidays so they may have forgotten to mark it received.  I've forgotten to mark books received before, but I check in here every day, so I usually catch it within a day or two.

I am in similar situation but I rec'd the wrong book!   So sender is going to send me correct book, then I will mark it received!

I offered her a choice from my shelf which I will "friend " her once the correct book arrives.  I figured it wasn't fair to get 2 books for 1 credit and the mistake looks like a good read.

There's nothing "unfair" about you getting 2 books from her for 1 credit if she made the mistake.  Now you have to spend postage money to send her a book of yours and then postage money again to get a credit for the wrong book she sent you.  Although if it had turned out to be one of my WL books that she had accidentally sent me, then I'd probably buddy a credit for that book and waited for the one I was expecting.

Yes Penny, it is ok to politely inquire.  Keep in mind that delivery confirmation only confirms that the package was delivered somewhere and does not guarantee it was delivered correctly.  Also, your receiver could be out of town for the holidays.  In addition, some PO's use incorrect scans for packages...this could merely mean 'arrived at unit' and could take several additional days to actually be delivered to the addressee.

These things can be a bit trixy, if the book is genuinely missing then the sooner the PO begins it's search the more likely it will be found.  OTOH receivers can become cranky if contacted too soon, but given the time passed this should not be the case for you.

Ask if the book has been received, if not you would like to assist in helping the package arrive at it's correct destination.  Do you have DC numbers from a source other than PBS?  If so (and the book has not been received) your PO can probably begin a search using your numbers.

Not a problem at all to send a reminder as long as you are polite. This happened to me recently and this is what I wrote:

Hi xxxx,

I hope you are enjoying the Holiday season.

I mailed your book with delivery confirmation and it shows delivered a week ago on the X. Can you please let me know if you got it? If you did, please mark it received so I can get my credit. :)

Thanks,

Since there has been two, three day holdiday weekends, I'd wait to PM.  Lots of people are busy coming and going and probably are just today beginning to get back to their normal routine.