Did you suspect there ws going to be another series abot camp half-blood?

Yes, because:

1. In the end of TLO Poseidon says he will see him again soon which either implies that he knew what would happen or he just wanted to visit his paborito son :)
2. The prophecy at the end, duh. I mean why would RR put up a walang tiyak na layunin (or at least at the time) prophecy at the end of the book, not go into it, and leave the readers to go crazy thinking about it? Why? He wouldn't, that's why. Pwned... XD (sorry, kinda hyper today...)
3. In the last two pages of TLO, RR could have made the moment with Percy and Annabeth carefree and happy but he put in the part where they start talking about the prophecy before they have their happy ending and all that. Why? Foreshadowing, that's why. O.o
4. If you flip to the page after the last page of the story of TLO, it talks about all the people RR would like to thank. It starts sa pamamagitan ng saying "As the FIRST Camp half-blood series comes to an end..." So yeah...first. Enough said.

The fourth reason is kinda small and unnoticeable unless you're like me and actually read the pages before and after the story but when I first read TLO, I was suspicious of another series coming up every time it reached one of the scenes listed above, but I wasn't entirely sure until I came upon the fourth reason I put up there.

So...yeah, hope this helped you...understand whether or not people knew about this series before it was released...yeah let's go with that.

Yes. I remember Rick hinting at it in the end of The Last Olympian.

Kinda

Cuz of the 2nd great prophecy,
And annabeth says it's for another generation of demigods, but I'm like ya rite, u guys don't have that much luck :P

Yeah cuz of the whole "the first camp half blood series" thing at the end of TLO

Yea
i was a late blommer and read the series when they all were written so i grabbed all the books at once and read them in two weeks then i thought i was done then my friend comes up to me and tells me that in two weeks the susunod series book one comes out and so i reread the series again and then the Nawawala hero so i never had to wait i all ready new there was two series

PS waiting sucks!!!

I figured that there must be because of the segundo Great Prophecy Rachel spoke of. Then, afterwards, Annabeth is thinking about it and keeps saying that there will be so many new faces susunod summer. Also, when most series end, the may-akda sort of wraps it all up and leaves no tanong left unanswered. Sometimes they even ipakita where they are 10-20 years later. For example, in the Harry Potter Series. J.K. Rowling wrapped everything up, showed where they were in I think 18 years, and left it with no tanong unanswered- at least, I did not have any tanong that were not answered. But, at the end of The Last Olympian, they left the segundo Great Prophecy unanswered, and a lot of other stuff (what they will do when they grow up, who they will marry, etc.) walang sagot as well. So to me, it just did not sound finished.