I have been waiting for two books that the sender marked as sent on 10/18.  The sender used DC, but the only details are that the Electronic Shipping Info was Received on the 18th.  There was no indication of acceptance by the Post Office.  I'm beginning to wonder if the books were ever REALLY mailed.  Should I be concerned?  Should I send a personal message to the sender?

That message just means that the DC number was generated. With no other entries, it's quite possible they were never mailed, though the post office is only really required to scan on delivery so they may have been mailed and just not arrived yet. At this point, enough time has gone by that a PM wouldn't be out of line. I would probably send one myself in about a week, and I'm in Alaska.

Electronic Shipping Info Received means that at DC number has been assigned.  On it's own, this entry  provides no information as to whether or not the book(s) has been mailed.  ACCEPTANCE entry means the member purchased posage at the PO, and the package has been mailed. 

If the sender used printable postage and a blue box, it is possible the package will arrive without being scanned enroute.  Delivery Confirmation is the only required scan for this service, enroute scans are a bonus.  I'm often suspicious when no acceptance or traveling entries are recorded, but have received packages only to check the postmark and realize they really were mailed on/near time.

PBS guidelines discourages contacting the sender before four weeks, my patience is sometimes overwhelmed around the three week mark. But if you do pm, keep in mind that the other member may be impatiently waiting for you to hurry up and mark the book received...so a very polite inquiry is the best option.  Some members approach the situation along the lines of...just wanted to let you know I'mnot ignorning you, the book hasn't arrived yet, should I be concerned?

ETA - rumor says the USPS website may have slightly different or more accurate info, you may wish to check the DC number there as well.

I mailed one book on Saturday and one on Monday from the same blue box, not at a post office.  I use this blue box all of the time because it is near my house.  Neither book has any notation but the electronic shipping info.  Usually there is a scan that night.  I was considering PMing the people to tell them I really did ship it but it's probably a bit too early, huh? I used the quick credit so that isn't the problem, I just don't want them thinking I lied.  I guess there wouldn't be too much point in lying about it though, the postage was obviously paid for.

Was the book mailed from a APO, FPO or DPO address? I mail from a DPO address. My books don't get scanned until they reach the sorting facility in New Jersy or New York. I mark them mailed as soon as I take them to my mail room at the embassy, but it sometimes can take an extraordinarily long time to get to New Jersy. Now that we've enterred the holiday season, things are REALLY slowing down. It used to take about 6 days. I just looked and I'd mailed some books on 10/14 that were just scanned into New Jersy yesterday (11/4)!

I always use the DC feature, however, to give more of a guarentee to folks that I've actually mailed the book. If I've paid for the postage and the DC, why wouldn't I mail the book? I do try to PM people to tell them it may take a bit longer to get books from me, but if I were in the States, I wouldn't do it just because it wasn't scanned again.

I like to keep track of my books that go out. Sometimes they seem to sit at the P.O. for a week or so without being scanned. Then suddenly they are scanned and rushed cross country, like to make up for the time they were sitting. Weird.

I've had that happen to me, too--I use PBS printable postage all the time now. I use the same blue box in front of my work. I've dropped multiple books in there on the same day at the same time...usually they all get a scan in Minneapolis later that evening, but occasionally (for who knows what reason!) there will be (for example) 4 that got scanned and one that didn't. Sometimes there will be a scan along the way, other times the book is marked received before there is any scan recorded at all.

Cheryl